After rigorous testing by the Hammacher Schlemmer Institute this autonomous pool cleaner was rated best because it easily scaled pool walls while its powerful rotating brushes, blowers, and vacuum dislodged and removed stubborn detritus. Unlike lesser models that could not climb walls and repeatedly cleaned the same spots, this one moved systematically throughout a pool, vacuuming all debris without once retracing its route. It suctioned leaves and grass clippings from the waterline and removed coins and sand on the bottom of the pool on the first pass, while other models failed to pick up the coins and capsized while cleaning the water surface. Capable of cleaning any residential pool up to 50' long in one hour, the unit has four cleaning programs that automatically accommodate different pool layouts, unlike lesser models that have to "learn" pool dimensions. Scoring highest for features, the best robotic pool cleaner has a reusable 19-quart capacity filter that removes microorganisms as small as two microns, it filters 5,000 gallons of water per hour, and has a remote control for spot cleaning. Cleaner operates independent of pool power; plugs into GFCI outlet. With 75' floating power cord. 13" H x 15" W x 16" L. (19 lbs.)