Amsahr Replacement Battery for Lenovo ThinkPad T420, E40, E50, ThinkPad Edge: 0578-47B - Includes Mini Optical Mouse Includes Mini Optical Mouse with Retractable USB cord and ONE Compatible Laptop Battery 18 Months Manufacturer Warranty, 100% Compatible Non-OEM : Lithium Ion (Li- ion) Long Life Battery: Rechargeable with No Memory Effect and Power Surge Protection. 7800 mAh, 10.8 Volts & 9 Cell Protective Retail Packaging, Each Product is Sealed with Anti-Static Shield Sleeve. Exclusive Offering of High Performance, Long Lasting, and Durable Grade A Cell Battery Includes Mini Optical Mouse with Retractable USB cord and ONE Compatible Laptop Battery 18 Months Manufacturer Warranty, 100% Compatible Non-OEM : Lithium Ion (Li- ion) Long Life Battery: Rechargeable with No Memory Effect and Power Surge Protection. 6600 mAh, 10.8 Volts & 9 Cell Protective Retail Packaging, Each Product is Sealed with Anti-Static Shield Sleeve. Replacement Laptop Battery for Lenovo T420 Non-OEM Battery Long Life, Li-ion Battery Rechargeable with No Memory Effect and Power Surge Protection. Exclusive Offering of High Performance, Long Lasting. Durable Grade A Cell Battery.