Stay unplugged longer with ThinkPad batteries. Provide up to one-third more capacity than the standard system battery. This high capacity battery has an extended area on the back edge and fits in the standard ThinkPad system battery slot. Its compatible design allows it to be in the system when the system is connected to the ThinkPad Advanced Dock, Advanced Mini-Dock, and Essential Port Replicator. Battery life (and recharge times) varies based on many factors including screen brightness, applications, features, power management, battery conditioning, and other customer preferences. (For battery life, go to lenovo.com/alldaycomputing)Supports T500, R500, W500, SL300, SL400, SL500, Z60m, Z61m, Z61e and non 14Wide T60, R60, T61, R61 ThinkPad models (does not support 14.4'' wide models) Up to 1/3 more capacity than the standard system battery to stay unplugged longer Nine-cell, rechargeable system battery, 10.8 V, 7.8 A Original equipment specifications for correct fit and capabilities And it's backed by a Warranty by Lenovo with renowned Service and Support available from IBM