The best robot lawn mower may be the ideal garden technology for 2021. Everyone is likely to be out and about this summer, more than ever before, after seasons of being cooped up indoors, and a mechanical lawn mower can keep yard maintenance simple while you’re resting and absorbing the rays.
With today’s technology, mowing lawn may be a “set it and forget it” proposition, but what other robot lawn mower is best for you as well as your yard?
We studied and rated the top ten robot lawn mowers in terms of price, size, and efficiency, so you don’t have to wade through the hundreds of choices on the market.
Though you’re worried about spending your summertime mowing the grass, a robot lawnmower may be a simple solution. But, of course, you could employ a professional lawn home care rather than a robot to take care of your grass.
If you determine that a robotic lawn mower is the best option for you, our top choices are among the finest on the market.
And use what you understand about your grass and the information in our buyer’s guide; you must be able to choose a robot lawnmower that allows you to set it and leave it when it refers to mowing your lawn.
Best Robotic Lawn Mowers 2021
1.WORX WR150 Landroid L Most Suitable Robotic Lawn Mower
If your yard is too large, then WR150 Landroid L from WORX is your best choice. This mower can handle yards up to a quarter in size and slopes up to 20 degrees.
The Landroid is “smarter” than many of our other top choices, with built-in Wi-Fi connectivity and a smartphone app that allows you to monitor the mower’s progress, evaluate your lawn, and modify your personalized mowing program from anywhere.
The Landroid is intelligent enough to suggest a lawn-care regimen depending on the length and other factors.
The rain sensor on the mower prevents it from running in the rainfall to eliminate the clumsier cut that results from mowing wet grass.
Precision cutting with the Landroid WR 150 is better than with many of our previous top choices, so that it may be the best option for yards with many landscapes and other obstacles.
When the Landroid comes across an impediment, it will gently bump it and then walk around.
Furthermore, it can traverse tight passageways better than previous robot mowers thanks to sophisticated AI technology.
Landroid WR 150 mows nearer to borders due to the “cut to edge” cutting design, leaving you with little edge clipping to perform afterward.
· 0.5-acre mowing area
· 9-inch cutting width
· Cutting incline: up to a 20-degree slope is possible.
· The cutting heights vary between 1.5 and 4 inches.
· Voltage: 20 volts
· Level of noise: 63 decibels
· Intelligent AI technology capable of navigating hurdles and breaking out of tight situations on its own.
· A wide variety of cutting heights is available to manage various kinds of grass and terrain.
· WORX Power Share battery is suitable with 20V and 40V tools.
· Occasionally gets entangled in dense vegetation.
· Some customers reported having difficulty placing the boundary wire.
· According to some users, the WR150 takes some time to learn how to traverse the yard independently and requires “babysitting” at first.
2.Husqvarna Automower 430XH Robotic Lawn Mower
It is primarily intended for medium to extensive gardens, and it has double the power and battery life of the lesser prototype Husqvarna Automower 430XH.
If you’re looking for a robotic lawn mower that can manage up to 3 inches of grass and attaches to your phone for simple operation, look no further.
It has GPS capabilities, operates even in the rain, charges in 50 minutes, and has a mowing duration of up to 150 min on such a single charge; this is the device to have!
It’s primarily intended for large lawns that need regular mowing and has many barriers and inclines.
It’s also famous for sports grounds and has a wide range of commercial applications.
It not only relieves you of the tiresome job of mowing your garden, but it also does not need you to get off of your chair to boot up when the grass needs a little trimming.
It communicates with smart home devices such as Amazon Echo and Google Home. That is, all you do to get it started is offer it a basic voice command.
It will wake up immediately and begin mowing your lawn quietly, returning to its charger when it needs more power or the job is completed for the day.
When there is anything wrong with the gadget or a malfunction occurs, the lights notify you. They also aid insight and control in the dark since it is so quiet that you might not be able to hear it approaching most of the time.
It’s one of the few fully GPS-enabled robot lawn mowers on the market, mapping your yard boundaries using satellite data.
This prevents it from wasting time and power supply mowing areas that have previously been mowed.
However, because of the grass’s kind, length, and depth, certain areas of your garden may need particular care and attention.
When the 430X’s sensors detect that a part of your garden is not up to pace with the remainder of your garden, it automatically changes its cutting pattern. It focuses more on that area using GPS technology.
It a must feature if you need uniformly trimmed grass. The Husqvarna 430X is a commercial, extreme-duty robotic lawn mower that can tackle slopes of up to 45 percent! Even when it’s pouring, and the ground is slick.
Even though it does not need as much care as a gasoline lawnmower, robot mowers are not free, irrespective of the brand or type.
However, the process could not be more straightforward since there is no need for an oil change, gas refills, or spark plug changes.
Switch the gadget off for security, flip it over, and inspect each of the three cutting tools and the round plate.
Ensure that they are still sharp. Husqvarna robotic mowers have nine replacement blades. Feel free to swap them out if necessary.
After you’ve checked the blades and made sure they’re still sharp, grab a stiff brush and wipe up all the grass clippings and remnants that are left beneath and around the device to improve the life of the Husqvarna 430X robot lawnmower.
This gadget is ideal for anybody who doesn’t mind paying a premium for a heavy-duty device for business or personal usage if you need a somewhat less expensive option that is not intended for professional use.
· The voltage is 26 volts.
· Capacity of the working area (20): 0.8 acre
· Cutting Height (minimum-maximum): 50-90 mm
· Typical mowing time on a single charge: 145 minutes
· Cutting heights range from 2 to 3.6 inches.
· Sharp-cutting width for quicker mowing.
· Wide variety of cutting heights
· The powerful battery, when compared to others
· Connects to Alexa on Amazon
· There is an ECO option that consumes less power and increases battery life.
· In comparison to others, this procedure is very loud.
3.Husqvarna Auto Mower 310 High-quality Lawn Mowers
Do you want the advantages of a Husqvarna-specific brand but without the high price? This type is appropriate for small lawns of approximately a quarter acre in size, and it can climb slopes of up to 22 degrees.
While the 310 is as powerful, you can still rely on Husqvarna’s superior technology and decades of expertise in producing a wide variety of high lawnmowers.
Unlike the 450X, the Automower 310 cannot be controlled anywhere in the globe.
It does, however, connect to Bluetooth, and the associated Connect@Home app allows you to modify parameters within 100 feet of the docking station.
The 310 lacks built-in GPS as well, which is a drawback in terms of navigation and security. However, you can be sure that it will provide a clean-cut, and it will even return fine grass cuttings to your yard as mulching to improve the soil.
Furthermore, this mower runs softly enough (maximum 60 decibels) to be used whenever you choose.
· The voltage is 18 volts.
· 0.25-acre mowing area
· 8.7-inch cutting width
· Cutting slope: up to a 22-degree slope
· Cutting heights range from 0.8 to 2.4 inches.
· The noise level is 60 dB.
· In comparison to others, it is less costly;
· It operates quietly;
· Not suitable for extensive lawns In comparison to others,
· The battery is inadequate.
4.Gardena 4069 Best Lawn Mower
The Gardena 4069 is designed to be lightweight. With a weight of just 16.5 pounds, you’ll have no difficulty getting this off the garage’s top-shelf.
The blade length is adjustable from.7 to 2 inches and is easily adjusted using the top-mounted knob. The Gardena, which can mow approximately 80 – 90 square meters, is clever enough to restore to its base station when the power runs out.
A robotic lawn mower is suitable for all kinds of gardens. Autonomous, silent, energy-efficient, and zero-emissions!
It’s easy to use, easy to install, and easy to maintain. Perfectly safe and fully adaptable!
In that regard, this model will provide you approximately one hour of mowing time. Although it does not have the most extended duration in our collection, it is still very competent for tiny yards.
· Dimensions are 24 x 16 x 8 in.
· 800 square meters of the cutting area
· Cutting heights ranging from.7″ to 2.”
· The Rechargeable lithium-ion battery with a capacity of 18V 1.6Ah.
· 16.5 Pounds Item Weight
· The grass looks beautiful like it’s never looked before
· It’s quiet and works well in the PNW wet weather,
· It’s simply programmed,
· It’s inexpensive compared to other comparable items.
· Simple to use
· Lack of remote programmability
5.Husqvarna Automower 115H Robotic Lawn Mower
The Husqvarna 115H is simple to use and modify. With such a robotic lawnmower, you can have a lovely lawn all the time. It is ideal for medium-sized yards (up to 0.4 acres) since it cuts less grass more often, resulting in a smooth, carpet-like look.
With Husqvarna Automower 115H Robotic Lawn Mower operates silently and independently, making lawn care a breeze.
It’s a dependable machine that can manage lawn care for yards of half an acre or less, with gradients of 22 degrees less than and grass heights of 2 to 3.6 inches.
This lawn care equipment can be controlled by your cellphone and its LCD screen, which allows you to personalize the settings. Unfortunately, its battery might last for a little more than an hour on each charge.
Regarding voice command technology, the Husqvarna 115H Connect is also one of the best robotic lawnmowers on the market. This mower is compatible with Android Assistant and Alexa.
Like a mulching mower, this safety-improved mower clips grass a bit at a time while enriching the soil.
You may program precise instructions to begin, stop, halt, or position your mower, as well as adjust the scheduling for your lawn maintenance, among other things.
Check out our listings of the most delicate spray nozzles, herbicides, and lawnmowers for your yard if you’re seeking to extend your lawn care equipment.
· Medium lawn up to 0.4 acres
· Height up to 2 to 3.6 inches
· Compatible with Google Assistant voice
· Auto adjust the position
· Adjust the scheduling
· Weight: 20 pounds
· Maintain your property in the best way.
· Good battery life
· Lawn care equipment
· Finest spray nozzles
· Compact size
· Easy to set-up
· Plenty of wires and cables are required
6.WORX WR140 Landroid M 20V Power Share Robotic Lawn Mower
The Automower WORX WR 140 is the finest robot lawn mower for large properties and doesn’t mind spending a little more money on a power tool. This mower can cut more than just an acre in a single cutting session.
A highly autonomous robotic lawnmower can trim up to 14 acres of grass. APP can operate and control in real-time.
A unique mowing AIA cutting system allows it to move through tight pathways quickly. Layered UI with intuitive controls for creating personalized work schedules.
Cutting on hills and slopes is now possible thanks to innovative electronics. Cut to Edge – An offset 3-blade cutting/mulching device for cutting closer to the edge.
Two brushless wheel motors that work independently. The rain sensor instructs it to return to the charging station.
This massive robot mower, however, comes at a premium price. The mower’s GPS-assisted navigation allows it to navigate tight passageways, challenging obstacles, and rough terrain on its own.
If you still want to keep in on your mower, you may use the Automower WORX WR 140 Result data to do it from anywhere. The software allows you also to track but also operate the mower from a distance.
It is tranquil in addition to being capable of handling significant and complex yards. It is the quiet mower on our list, with a sound power production, so you can probably use it at any time or day-night without bothering anybody.
· Mowing area:0.4 acres
· Voltage: 20V-40V
· Cutting height is 5 inches in length
· The width is 7 inches.
· In weight: 21.20lbs.
· It cuts the grass efficiently
· Easy to use
· Battery life is good
· Leaf blower
· Highly recommend
· Zero fumes
· Reduced noise
· GPS not supported
7.WORX WR153 Landroid L 20V Power Share Robotic Lawn Mower
WORX WR 153 has created robot lawnmowers that have gained popularity due to their value in terms of functionality and pricing.
WORX WR153 Landroid L lawn mowers are entry-mid level, inexpensive lawn mowers for lawns up to 0.5 acres in size. They will return your Sunday evenings to you to spend with your family.
Worx WR 153 robot mowers are intended to automate 99 percent of your lawn-care tasks. These self-contained devices can mow the grass anytime, day or night by trimming it in short bursts.
The WR153 automated lawnmowers mow the grass in a complex pattern using a “mowing algorithm.” This technique guarantees that your grass has always been at the correct level and that your carpet is smooth.
Because of their tiny size, little grass clippings from robot lawn mowing serve as a natural fertilizer. They are readily absorbed by the lawn and soil, promoting new growth and fuller grass.
The cutting height may be adjusted manually, allowing you to have grass heights ranging from 1.6 to 3.9 inches. If you want a specific inch of grass height, just specify it.
With the cut-to-edge function, they also can cut nearer to the corners than other robotic mower types.
They, like other robotic mowers, are intended to trim your grass a few at a time, but frequently. This guarantees that grass clippings are so tiny that they do not need to be gathered and discarded.
It is designed for medium-sized yards ranging up to 0.5 acres in size. This size is determined by many variables, including the battery’s mow and charge times, the pace with which they mow the lawn, and the length of the cutting deck.
The cutting deck is simply the size of the surface underneath the mowers and the cutting breadth of the blades. Both versions feature a 9-inch cutting width deck with a three-blade rotating disc.
The chopping board has a Dynamic Deck design, which is not seen on conventional mowers. In addition, the floating deck accommodates uneven lawn topography and tall grass automatically.
The Landroid will modify the mowing deck low and high as it moves to detect various grass height levels. This is useful for cutting on more challenging terrain and hills.
The most extended component of the operation is installing the boundary wire. Border wires should be established together with all way all-around the perimeter of your lawn, as well as around permanent barriers like shrubs and trees.
The WR153 has the same design as the WR153, with the bulk of the functions located on the top of the lawnmower for easy access. On top is the detachable and renewable lithium battery pack. As a result, there is no need to switch the mower over to replace the battery.
Depending on the grass topography, the new 4.0Ah rechargeable batteries provide a mowing duration of 60-90 minutes. The battery will usually recharge in 90 minutes after its first charge, which takes longer.
The silence of these lawnmowers also allows you to use them at night without disturbing anybody.
· The voltage is 20 volts.
· 0.5-acre mowing area
· 9.5-inch cutting width
· Cutting incline: up to a 30° slope
· Cutting heights range from 1.6 to 3.9 inches.
· In comparison to others, it is less costly.
· It also includes a larger battery.
· Simple to set up and manage
· There are many safety features.
· It is not suitable for extensive lawns,
· Not Smart Integration
8.Husqvarna Automower 315X Robotic Lawn Mower
The Husqvarna Automower 315 is an excellent robotic lawn mower that offers excellent terrain handling and dependability with an easily programmable interface and sophisticated navigation solutions.
The guidewire is also a fantastic addition. For example, if you have a yard with a complex form or several zone work zones, the guide cable allows the robotic lawn mower to make its way out and back simply.
The Automower 315’s terrain-handling skills are exceptional, and it rarely gets stuck. It can also easily tackle steep slopes, obstructions, including pavement somewhere on the lawn.
It’s also tranquil and powerful. It may be out chopping for an extended period. The Automower 315 comes with app compatibility, and the software is very user-friendly.
You may simply modify parameters like start points, manually cutting height modification and new schedules with this.
Even when changing settings directly on the machine body, the robotic lawn mower is extremely simple to configure. The display is big and simple to see, and the interface is split so that even inexperienced users can comprehend it.
Ultimately, the Husqvarna Automower 315 is an excellent choice for anybody looking for a dependable and simple-to-use robotic lawnmower.
It is appropriate for anything from essential, manicured lawns to uneven, complex multi-zone variations with several cutting zones.
The Automower 315, on the other hand, is the most excellent better value on more challenging lawns that can truly show off what it can accomplish.
· Maximum area: 0.4 acres
· Maximum gradient: about 14°
· Cutting height: 0.8-2.4inches,
· Cutting width: 8.7 inches
· In weight: 32 pounds
· 60 decibels of noise
· Excellent terrain-handling abilities
· Easy to programmable
· Excellent app
· Bodywork that is easily scratched
9.WORX WR143 Landroid M 20V Power Share Robotic Lawn Mower
Worx’s WR143E is our biggest midrange robotic lawnmower for lawns up to 1,000 m2.
It is quicker and more efficient than previous robotic mowers due to sophisticated scheduling and navigation.
The WR143E comes with Trim to Edge, which allows you to go as near to the side of the grass as possible.
Android is safe and silent, and it includes a battery that is compatible with any Worx 20V rechargeable battery.
Customized mowing schedules are an excellent option to have so that you may continue to use the yard.
They also feature tilt and raise sensors, which stop the cutting blades immediately if anybody tries to shake the robotic mowers.
The Landroid L mowers will need a PIN to resume after being lifted to anti-theft measures.
Another helpful feature is the Installation Lock, which prevents the mower from operating on lawns that’s not yours. It will only run on the first lawn it was set up for.
While you should keep them as protected and dry as possible, they will more than withstand the challenges of mowing all kinds of grass throughout the growing season.
They can cut in the rainstorm, but wet grass is not a good idea. Grass clippings may clump together and cause problems with tires and other components getting stuck.
It is suggested that you store your mower inside when you will not use it for an extended period, such as during non-growing seasons, to extend its life.
The bottom and wheels must be cleaned and inspected regularly. When the blades lose their sharpness, they should be replaced as well.
Based on the grass variety, thickness, and frequency of mowing, you may anticipate a set of blades to last two to three months. It is a dependable and simple-to-use robotic lawn mower that outperforms the competition.
It’s ideal for anybody with other products to integrate into a single, intelligent system.
· Voltage: 20 volts
· Maximum area: 1000 m2
· Maximum gradient: about 20°
· 30-60 mm cutting height (manual)
· 180mm cutting width
· 9.4 kg in weight
· 67 decibels of noise
· Reliable, user-friendly interface
· Excellent problem-solving abilities,
· Ease of maintenance
· App with limited functionality
· Wi-Fi necessitates the use of an extra gateway, resulting in somewhat lower performance.
10.WORX WR155 20V Best Robotic Lawn Mower
The WORX WR 155 is a dependable robotic lawn mower that is simple to set up and operate.
It rarely gets stuck as much as the lawn is maintained short. However, if the grassland has risen a few centimeters, it will have difficulty finding its way back home.
The Worx Landroid L is around to help more extensive lawn owners reclaim their Saturdays. It has a powerful 6.0Ah high-capacity Power Sharing battery and a larger 8-in.
Mowing width can cover up to 12 acres. Once you’ve installed your Landroid, you’ll never have to trim your grass again.
The all-new Worx Landroid L WR155E is our most giant robot mower, capable of mowing a field up to 2000m2.
It is quicker and more agile than other robot mowers due to Smart Auto planning and sophisticated navigation.
The WR155E has cut to Edge, which goes as near to the edge of your grass as possible. So Android is safe and silent, and it includes such a battery that is compatible with any Worx 20V wireless instrument.
Its structure is so delicate to roadside accidents that a wildflower plant may throw it off. Moreover, if the grass surrounding the guidewire is long, it will have trouble finding its route before the battery dies.
However, configuring the robotic lawn mower through the LCD monitor is extremely easy. The user interface is well-designed and easy to use, and the display has excellent contrast and works well even in direct sunlight.
It is perfect for individuals with a small to medium-sized yard seeking a low-cost but dependable robotic lawn mower with user-friendliness – and, ideally, those who want to build a better garden in the future.
· It charges itself automatically.
· Maximum area: 2000 m2
· Maximum gradient: 25%
· 30-60 mm cutting height (manual)
· 8 inches cutting width
· 44.1-pound weight
· Noise level: 66 decibels
· High dependability
· Installation is simple.
· The display makes programming a breeze.
· App support is less effective in thick grass and necessitates the use of a separate router.
Buying Guide for Best Robotic Lawn Mower
Robot lawnmowers haven’t been around for very long, but nobody can blame you if you don’t know what you’re searching for.
While we can’t tell you which choice is ideal for your yard, we can describe some of the specifications you’ll see on a robot mower’s product description but what those numbers represent.
These are the criteria we used to select our top choices, and these are the criteria you should consider while comparing different models:
Voltage: The first thing you should know about a robot mower’s battery power is its voltage. The higher the voltage of the battery, the greater the power output of your mower.
More energy means the mower can handle thicker and lengthier grass. As a result, a mower with such a 28-volt battery (such as our top choice) would be more suited to cutting extensive lawns than someone with, for example, an 18-volt battery.
Mowing area: When it comes to robotic mowers, this is perhaps the essential statistic to consider. The mowing area of a robot mower is the largest yard area it can manage.
If you have a complete acre of grass and select a robot mower with just a cutting area of 1⁄4 of an acre, just a portion of it will be mowed.
But on the other hand, if the yard is just a quarter of an acre when you purchase a mower designed for an acre more than, you’re paying much more money than necessary since smaller mowing areas typically imply cheaper costs.
Cutting width: Just like any conventional lawnmower, the chopping width indicates how often ground a robot mower can cover in a single pass.
Larger cutting widths imply doing the task quicker.
Of course, the pace of the task isn’t as important with just a robot lawnmower as it is with conventional mowers since you won’t be performing some of the work personally.
Cutting inclination: The most incredible cutting incline of a robotic lawn mower is the steepest slope it can climb.
If you have an elevation in your yard, be sure you know how steep it is so you can pick a robot mower that can climb it.
Cutting heights: Many lawnmowers, automated or not, feature various cutting height settings, allowing you to choose the size of your grass.
To adjust the cutting height, raise and lower the chopping deck, typically accomplished with a primary button or slider on the mower.
Some mowers offer a wider variety of mowing heights than others, which implies they are better suited to a wider variety of terrain and grass kinds.
Noise level: The amount of noise produced by your lawnmower is particularly significant if you live in a town with near neighbors.
Because batteries power all robot lawn mowers, they are considerably silent than a gas mower. Although gas lawn mowers generate approximately 90 decibels of noise, robot mowers produce between 60 and 75 decibels.
Even while all robot lawn mowers are pretty quiet, if you want to schedule your automated mowing for the evening, you should choose one of the most modest versions.
Price: As you are undoubtedly aware, robot lawn mowers are significantly more costly than any kind of push or self-propelled leaf blower.
It’s only reasonable to pay a high fee for the ease of never needing to mow the grass again.
Higher-end mowers are typically more expensive since they have a more extensive mowing area and many high-tech features.
Unique characteristics to keep an eye out for
Aside from these fundamental requirements, robotic lawn mowers may offer a variety of unique features. Here is one of the most frequent ones you should look into:
GPS tracking: The GPS in a robotic mower performs many functions. For example, it may aid the mower’s navigation of your lawn and is helpful for security.
If someone takes your mower, you’ll be able to quickly trace it down, recover it, and apprehend the offender.
Even though your mower is not stolen, GPS monitoring allows you to keep track of its location at all moments for whatever purpose.
All-wheel drive: This feature is uncommon in robot mowers, yet none of our top choices have it.
If the yard has many rough terrains, steep hills, or other difficulties, you may need to invest the extra funds for a supporting framework with an all-wheel drive.
Wifi connectivity: When most robot mowers link to their respective smartphone applications through Bluetooth, this generally does not enable you to operate the mower while you are away from home.
You should be able to access your mower from anywhere in the globe if it can link to your Wi-Fi.
Compatibility with “home automation” virtual assistant systems like Amazon Alexa or Google Home: Some robot lawn mowers can link to “smart home” virtual assistant devices such as Alexa Voice or Google Home.
With this functionality, you must be able to issue a voice command such as “Alexa, mow the grass,” and the robot lawnmower will be deployed on demand.
PIN code security: For further protection, certain robot lawn mowers will only operate after you input a secret PIN, comparable to checking your phone with a password.
A robot mower with a Password would be worthless to a thief, much as a protected phone would be to a burglar.
Frequently Asked Questions
Are robot lawn mowers effective?
One aspect that robot lawn mowers excel at is improving the quality and appearance of your grass. This is due to two significant factors. The first is to trim your lawn regularly. Robot lawnmowers are intended to cut your grass considerably more often than a standard mower.
Do robot lawn mowers pick up grass?
All robotic lawnmowers are mulch mowers, which means they do not gather the grass but rather cut it into fine clippings and disperse them to decay, allowing the nutrients to return to the soil. This implies that instead of mowing in random patterns, the mower may operate in straight lines.
How long will a robot mower last?
In typically, robotic mowers have a 10-year lifespan. However, this depends on the kind of grass you are mowing as well as other environmental factors. A considerably longer lifetime is achievable if appropriate maintenance is performed.
Why are robot lawn mowers so costly?
Robotic lawn mowers are considerably more complicated and challenging to build than conventional lawnmowers. Companies must employ developers and engineers to create and develop the product, and they must compensate them for their exorbitant salaries.
What maintenance does a robot lawnmower need?
You’ll have to clean the bottom of your robot mower regularly, just as you would with any other lawnmower, so that grass clippings, slathered dirt, and other waste don’t accumulate across the tires and other moving components slowing it down and possibly creating mechanical problems.
You’ll also need to change the blades regularly for optimum cutting effectiveness, but the frequency may vary according to the type.
It’s not strange that not every robotic lawnmower is created equal, and performance, efficiency, dependability, usefulness, and security vary more than you would expect across models. Nevertheless, we suggest that you get the Gardena 4069 since it is one of the finest robotic lawnmowers. It works well, and you don’t have to be concerned about your grass.