Stay unplugged longer with Think Pad Battery 29. This rechargeable battery uses Lithium-Ion (Li-Ion) technology & can be used as replacement for aging system batteries or as a convenient spare battery. Features Battery Capacity: 5200m Ah Battery Volt: 11.1V Battery Type: Li-ion Battery Color: Black Compatible with: Lenovo Think Pad X220 Series Lenovo Think Pad X220i Series Lenovo Think Pad X220s Series