Bay Valley Parts 6-Cell 10.8V 5200mAh New Replacement Laptop Battery for IBM Lenovo Thinkpad T410 T420 T510 T520 E40 E50 T520 E525 W510 W520 42T4751 42T4235 42T4737 Battery type: Li-ion; Capacity: 56Wh; Cells:6-cell; Voltage: 10.8V;Capacity:5200mah. Compatible Models: For LENOVO ThinkPad E40 E50 E420 E425 E520 L410 L412 L420 L421 L510 L512 L520 SL410 2842 SL410 2874 SL410k 2842 SL510 SL510 2875 SL510 T410 T410i T420 T510 T510i T520 T520i W510 W520 Part Numbers 42T4235 42T4708 42T4714 42T4733 42T4756 42T4764 42T4798 42T4803 42T4819 42T4848 42T4911 51J0499 57Y4185 57Y4545 ASM 42T4703 42T4752 42T4794 42T4702 replacement notebook laptop battery batteries High quality grade "A" cells. Charges quickly. Longer discharge time. Steady output and low power consumption. More than 500 times charge-discharge cycles.All products are Certified by CE ROHS UL1642 FCC for safety. Operation time for standard batteries(6-cell 5200mah): Around 2 hours the actual operation time will depend on how much electricity is required by the device and how you use it. 24 x 7 email support 12-month service. 12-months hassle-free warranty service. Please check if this battery is compatible with your computer before purchasing. Part numbers of compatible batteries and Computers are listed as following.