Amsahr Replacement Battery for Acer TravelMate 39D1, 91.42S28.001, BTP-39D1, BTP-620, 621EV, 621L, 621LC 18 Months Manufacturer Warranty, 100% Satisfaction Guaranteed. 100% Compatible Non-OEM : Lithium Ion (Li- ion) Long Life Battery: Rechargeable with No Memory Effect and Power Surge Protection. 4400 mAh, 14.4 Volts & 8 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