Lenovo ThinkPad Advanced Ultrabay Battery III. Battery capacity: 2900 mAh, Battery technology: Lithium Polymer (LiPo), Battery voltage: 10.8V. Width: 5.05 in, Depth: 5.45 in, Height: 0.41 in. Dimensions (WxDxH): 128.3 x 138.5 x 10.5 mm, Battery type: 3 Cell Li-Polymer