The ML-RMB500 battery is fully compatible with all Roomba 500, 600, and 700 series. Mighty Max ML-RMB500 Brand new Battery Pack which is compatible with iRobot Roomba Advanced Power System APS Battery. ML-RMB500 replaces the original iRobot Roomba 80501 battery. ML-RMB500 is an Ni-Cd Rechargeable battery that keeps Roomba running at peak performance, cleaning up your room in a single charge. ML-RMB500 can be charged or discharged as needed without loss of capacity.