Go to Amazon Sites : br br HP MU09 HPQIB1E WD549AA WD549AA#ABB 593550-001 593556-001 636631-001 DM4-1000 DV3-4000 DV4-4000 br br Type Li-Ion Voltage108V Capacity8800mAh12 Cells br 1 year replacement warranty30-day refund guarantee after the purchase br High Capacity Replacement battery br Each Superb Choice battery was tested at an original laptop by the manufacturer br If your original battery is a 6-cell battery this 12-cell battery has much higher capacity and works longer hours after each charge However it is bigger heavier and sticks out due to the extra 6 cells It will still fit in your laptop