Synergy Digital Tablet Battery, Compatible with Lenovo ThinkPad X1 3rd Tablet, (Li-Pol, 7.72V, 5050mAh) Ultra High Capacity, Replacement for Lenovo L16L4P91 Battery Specifications: Battery Chemstry: Li-Pol Voltage: 7.72V Capacity: 5050mAh Compatible with: Lenovo L16L4P91 Battery Works for: Lenovo ThinkPad X1 3rd Tablet and many more