Stay unplugged longer with these genuine Lenovo batteries. These rechargeable batteries use Lithium-Ion technology and can be used as replacement for aging system batteries or as a convenient spare battery.Lithium-Ion (Li-Ion) technology 6 cell system battery Over-discharge protection to prolong the life of the battery Battery energy (Watt-hours): 72Wh Battery Safeguard chip authenticates with Lenovo systems.