iRobot is beefing up its robot mop offerings by launching two new combo models: the Roomba Combo j5 Plus ($799) and the Roomba Combo i5 Plus ($549). These are combination cleaning bots that can mop and sweep simultaneously and come with a charging dock that also automatically empties their dustbins.

When the company’s first robot mop / vacuum, the Combo j7 Plus, launched last year, it was a few years behind the competition and slightly underwhelming. While the robotic arm on the j7 that raises and lowers the mop up and over the robot to avoid your carpets entirely is pretty cool, the mopping itself is less than stellar. (iRobot has had a very effective mopping-only line, the Braava Jet, for several years.)

These new models don’t have that arm. (They also cost well under $1,000.) Instead, when you want to mop, you switch out the rear dustbin for a dustbin / water tank with an attached reusable mopping pad. The robots will then mop as well as sweep. There’s no oscillating action like that found on competitors like Roborock; iRobot says the downward pressure and movement of the robot is enough to “scrub” your floor.

I’ve tested a lot of combo devices, and short of a system that automatically drains and refills the robot’s water tank, I like these swappable modules best. They get you the most water capacity without a pricey refilling dock and, therefore, the least amount of refilling. More water equals better mopping, in my testing.

The other option, where you attach a tiny slimline water tank to the bottom of the bot, barely does anything to mop and runs out of water in minutes. The new Roombas have 210mL mopping reservoirs, and the dustbins hold 360mL. Still, that’s smaller than the 300mL water capacity and 400ml bin capacity of Roborock’s similar models.

The downside is you have to remember to swap them back out when you want to vacuum your carpeted rooms, as neither model will automatically avoid carpets or rugs. The smarter Combo j5 will allow you to set no-mopping zones in the app, but the Combo i5 doesn’t have this feature, so it’s a better option for rooms without rugs.

Both new models come with an auto-empty charging dock, which iRobot calls a Clean Base. This empties the vacuum’s dustbin; it doesn’t get involved with the water side of things. That’s all on you.

The Combo j5 is part of iRobot’s high-end line, and the Combo i5 is in its midrange series. The current i3 Evo — which the i5 may well replace — is my pick for the best budget vacuum, and with the release of this model, it may see some significant price drops.

Both bots use iRobot’s OS, giving them features such as scheduling, shared maps, room-specific cleaning, and more. They both get around by using iRobot’s vSLAM navigation (visual simultaneous localization and mapping), but only the j5 has AI obstacle detection.

This is the most significant difference between the J and I series — and the reason you’ll pay $250 more for the Combo j5. The j5 can recognize household clutter, including cords, clothes, shoes, socks, backpacks, pet bowls, pet toys, and pet poop, so it’s less likely to get derailed during a job and finish cleaning.

Using its onboard camera, the j5 also recognizes objects like litter boxes, toilets, dishwashers, and more and can deploy custom cleaning around those areas. It also has a dirt detect mode that more thoroughly cleans dirty areas, which isn’t available on the i5.

While both robots can create and store maps of your home and clean specific rooms when you want (rather than the whole house in one go), only the Combo j5 allows you to set no-go and no-mop zones. The Combo i5 will go anywhere it can reach unless you also buy some of iRobot’s virtual walls.

The new Roombas work with Alexa, Google Assistant, and Apple’s Siri for voice control. They’re available for preorder in North America on iRobot.com and will ship in September. They’ll be available at other retailers beginning September 3rd. The Combo i5 Plus is available to order in Europe now, and the Combo j5 Plus will be available in September.