The Lenovo ThinkPad Battery 68+ is a 6 cell Lithium-Ion battery which lasts for 72 watt power battery with over discharge protection that help its long life rechargeable battery which has various factors including screen brightness, power management features and a chip to safeguard and authenticate overall system. Compatible with X240, X250, X260, X270, W550, W550s, P50s, L450, L460, L470, T440, T440s, T450s, T450, T460, T460p, T470p, T550, T560