CSEXCEL New Laptop Battery [Li-ion 6-cell 5200mAh/58WH] for Dell Studio 1535 1536 1537 1555 1557 1558 PP33L PP39L battery WU946 KM958 - 12 months warranty Battery type: Li-ion; Capacity: 5200mAh/58WH; Cells: 6-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.