LB1 High Performance Battery for Dell Inspiron M521R N5420 N5520 N5720 N7420 N7520 N7720 Fits: 8858X DHT0W Battery Type: Li-ion; Capacity: 4400mAh/48Wh; Cells: 6-cell; Voltage: 10.8V 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.