Lenovo Thinkpad Battery 81+
The 6-cell ThinkPad 81+ battery is compatible with T420s and T430s systems. These rechargeable batteries use Lithium-Ion and Lithium-Polymer technology to allow you to stay unplugged for longer. The battery lasts for 44 watt hours on average* and can be recharged with the ThinkPad External Battery Charger (40Y7625).