LB1 High Performance Battery for Dell Studio 1535 1536 1537 1555 1557 1558 PP33L PP39L Fits: WU946 KM904 Battery Type: Li-ion; Capacity: 4000mAh/44Wh; Cells: 6-cell; Voltage: 11.1V 100% Brand New from Manufacturer. Rechargeable Up to 500 times over life of battery. Premium Grade A cells ensures peak performance and reliability. Operation time depends on the capacity of the battery, laptop settings, power consumption of equipment, and how you use it. CE-/RoHS-/FCC- Certified and Built-in circuit protection ensure both safety and stability. Live Support Mon-Fri 4am-8pm PST | Sat-Sun 8am-5pm PST | 18 Months Hassle-Free Warranty.