Puwda T520 87Wh Battery for Lenovo ThinkPad E420 E520 T410 T420 T510 L410 L510 L520 W510 W520 Laptop Battery 42T4733 42T4757 [9-cell 11.1V 7800mAh] Battery type: Li-ion; Voltage: 11.1V; Capacity: 7800mAh/87Wh; Color: Black 100% New from Manufacturer. Up to 500 recharge cycles over the life of the battery. High Capacity Battery 55++; 9 Cell Extended Life Batteries will stick out of the battery compartment by 1 inch. One brand-new generic replacement battery for IBM Lenovo ThinkPad E420 E520 T410 T420 T510 T520 L410 L510 L520 W510 W520. Fulfilled by Amazon.