LION BATT 8CELL FOR X41 TAB ONLY Stay unplugged longer. Get twice the capacity of the 4-cell system battery and up to 7.5 hours of battery life on select systems. This high capacity battery has a notched design to accommodate tablet screen swivel hinge for notebook or convertible tablet function and fits in the standard ThinkPad X41 Tablet Series system battery slot. Its compatible design allows it to be in the system when the system is connected to the optional ThinkPad X4 Dock.