Tech Rover Replacement Battery for Toshiba Satellite M640-BT2N22 trade; Max-Life Series 12-Cell [Super-Capacity] 100% Compatible - Will not void your original laptop warranty Tech Rover&trade; Quality product with 30-DAY Worry-Free Return Policy Brand New Battery, 8800 - 10400 mAh, Effective Capacity All Tech Rover&trade; branded items carry a 1 year warranty against manufacturer defects. 12-Cell High Throughput Battery *Please note this an extended capacity battery and may protrude slightly from your laptop.