3500mah Battery for iRobot Roomba 400 4000 4100 4105 Roomba 4170 Roomba 4188 Battery type: Ni-MH; Capacity: 3500mAh Voltage: 14.4 V Compatible with: iRobot APS 4905 / Tenergy 11701 / Tenergy 11709 Grade A cells ensure fast charges and low power consumption; Built-in circuit protection ensures both safety and stability.