Battery for HP 636631-001 [11.1V, 9Cells] Laptop notebook pc computer for HP 24 Months warranty by CWK High Performance Condition: Brand New - Grade A cells Battery Type: Li-ion Voltage: 10.8 Volt (11.1 Volt compatible) Capacity: 7800mAh (Better than 6600mAh) 90 Day Money Back. Buy with confidence!