Stay unplugged longer with Lenovo batteries. This rechargeable 4 cell battery uses Lithium-Ion (Li-Ion) technology. It can be used as a replacement for aging system batteries or as a convenient spare battery. Battery life (and recharge times) varies based on many factors including screen brightness, applications, features, power management, battery conditioning, and other customer preferences. Supports T/R61 & T/R400 14.4" Wide Series notebooks