The ThinkPad 28++ 9-cell battery can serve as a more powerful replacement for your standard T or W-series notebook battery. These 94 Wh rechargeable batteries use Lithium-Ion technology and can serve as replacements for ageing system batteries. You could also use the ThinkPad 28++ battery as a convenient spare battery, to keep on hand when you need to keep your system powered for several hours on end. This ThinkPad battery is compatible with the T410/20/30, T510/20/30 and W510/20/30 series notebooks. It is compatible with the ThinkPad External Battery Charger and connection via a docking port.