The Think Pad Battery 17+ can help to keep your X100e system powered for longer. This 6-cell, 57 Wh, 10.8 VDC, 5.2 Ah rechargeable battery uses Lithium-Ion (Li-Ion) technology & can be used as a replacement for ageing X100e system batteries or as a convenient spare battery. The Think Pad Battery 17 is compatible with both X100e & X120e notebooks & offers over-discharge protection, enabling better battery life.