iRobot Advanced Power System Ni-MH Battery, 3000 mAh, 17373 Extended battery for Roomba 400 Series, Discovery Series, and original models Cleans up to 4 rooms in a single cleaning cycle 3000 mAh runs approximately 2 hours on one charge Charges in 7 hours with standard charger Charges in less than 3 hours using optional APS Fast Charger