CSE Extended life [7800mah 9 Cell 11.1V] Blcak Laptop Battery for Dell Studio 1535, 1536, 1537, 1555, 1557 Series WU946, WU960, WU965, MT276, MT264, KM905, KM904, PW773, KM887-12 Month Warranty Battery type: Li-ion; Capacity: 7800mAh/87WH; Cells: 9-cell; Voltage: 11.1V. 100% New from Manufacturer. Up to 500 recharge cycles over the life of the battery. CE-/FCC-/RoHS-Certified for safety. 24 x 7 email support,12-month hassle-free warranty. Grade A cells ensure fast charges and low power consumption; Built-in circuit protection ensures both safety and stability. Operation time: the actual operation time will depend on how much electricity is required by the device and how you use it.