Lenovo 57Y4536 Ultrabay III Notebook Battery

Swap out your optical drive with a second battery to increase your unplugged power supply. The ThinkPad Advanced Ultrabay Battery III fits neatly into the Ultrabay media bay of ThinkPad notebook Series, UltraBases. Achieve all day computing up to 8 hours or more when you use the ThinkPad Advanced Ultrabay Battery III along with a high-capacity system battery like the optional ThinkPad T/R 14W 9 Cell High Capacity Battery