Back in January 2011 iRobot announced the Scooba 230, its latest floor washing robot. It was built to bring the intelligence and usefulness of iRobot’s vacuuming bots (the Roomba series) to small, moppable spaces. The bot did its job well enough but its size meant it was slow and had a limited tank capacity, making it only good for bathrooms… and probably not worth the $300 price. iRobot hasn’t given up on floor washing though — the company is back with the Scooba 390, a full-sized bot that doesn’t require you to pre-sweep the floor.That last details is particularly important — the Scooba 230 was designed to work with floors that had already been swept and cleaned of any large debris. After that point it would lay down clean liquid, scrub back and forth, and then suck up the dirty liquid, leaving you with a pristine surface. The Scooba design, which was carried through to the 390, uses two reservoirs so soiled liquid is never reused.The biggest improvement with the Scooba 390 over the 230 is the presence of a rotating brush, the beater, which the 230 did not have. Of course the 390 isn’t a replacement for the 230 — that model will stay on sale — it actually replaces the Scooba 380. This model has the brush beater but is getting old and reviews on it were never great. The 390 attempt to specifically address the 380’s usability shortcomings, with improved user friendliness and up to 30% longer battery life. The 390 is said to use the 230’s improved, water-resistant battery design and be both easier to clean and empty than the older model. The Scooba 390 can wash areas up to 425 square feet, making for a bot that can handle much larger rooms than the 230’s 150 square feet. (The fluid capacity is unchanged from the 380 so that extra 30% battery life might not be as useful as it seems.) While cleaning the area it will guide itself with iAdapt just like any other Roomba, avoid rugs and carpets, and it can be set to pre-sweep areas before the wet cleaning begins. It also works with vinegar and water, as opposed to just iRobot’s branded enzymatic cleaner.The Scooba 390 will be sold through iRobot.com for $499.99.