Stay unplugged longer with these genuine ThinkPad batteries. These rechargeable batteries use Lithium-Ion technology and can be used as replacement for aging system batteries or as a convenient spare battery. Compatible with T410/20/30, T510/20/30, W510/20/30, L410/12/20/21/30, L510/12/20/30 Lithium-Ion (Li-Ion) technology 9 cell system battery Battery energy (Watt-hours): 94 Wh Compatible with the ThinkPad External Battery Charger (40Y7625)