Powerextra 7.2V 2200mAh Replacement Battery Compatible with iRobot Braava 320/321 & Mint 4200/4205 Battery Type: Ni-MH, Capacity: 2200 mAh, Volt: 7.2 V Battery Replacement for iRobot Braava 320/321 & Mint 4200/4205 High capacity Long Lasting battery replacement your Mint 4200/4205 Built-in protection against overcharging, over discharge, over current, provides short circuit protection and steady voltage circuit, all of these lengthen battery life All Powerextra products come with a 30-day money back and a 12-month limited seller's guarantee against manufacturer defects from date of purchase, and 24 hours' friendly customer service!