Amazon.com: Customer reviews: iRobot Roomba 640 Robot Vacuum – Good for Pet Hair, Carpets, Hard Floors, Self-Charging
Amazon.com: 1800LI Replacement Parts Battery for iRobot Roomba 985/980/960/600/700/800 Series Robots 614/615/640/652/665/670/671/675/677/680/685/690/695/790/780/770/760/700/801/805/850/860/877/890/891/895 : Home & Kitchen
Roomba 614 vs. 640 vs. 652 vs. 671 vs. 675 vs. 690
Amazon.com: Customer reviews: iRobot Roomba 640 Robot Vacuum – Good for Pet Hair, Carpets, Hard Floors, Self-Charging