Skyvast WU946 Extended Life [7800mAh 9 Cell] Laptop Battery for Dell Studio 1535 1536 1537 1555 1557 1558 PP33L PP39L Battery type: Li-ion; Capacity: 7800mAh; Voltage: 11.1V; Cells: 9-cell. Fit Laptop Models: Studio 1535 1536 1537 1555 1557 1558 PP33L PP39L Compatible P/N: A2990667 WU946 WU960 WU965 MT276 MT264 KM905 PW773 KM904 Warranty: 12 Months warranty, 30 days money return guarantee. Meticulous packed and fast shipped with multiple layers of protection.