Stay unplugged longer. Get twice the capacity of the 4-cell system battery and up to 7.5 hours(1) of battery life on select systems. This high capacity battery has a notched design to accommodate the tablet screen swivel hinge for notebook or convertible tablet function and fits in the standard ThinkPad X41 Series system battery slot. It's design allows it to remain in the system when the system is connected to the optional ThinkPad X4 Dock.