iRobot Braava 320 321 Rechargeable Ni-MH Battery Pack for Automatic Va – XML Battery
Amazon.com: HQRP 2200mAh Battery Works with iRobot Mint 4200, Mint 4205, Braava 320, Braava 321, 4408927 Automatic GPHC152M07 Ultra High Capacity [Robotic Vacuum Cleaner] : Home & Kitchen