Hyperion T-Mobile LG MyTouch Q 4G 2800mAh Extended Battery + Back Cover Extend your talk time on your LG MyTouch Q C800 phone. 2800 mAh Battery Capacity (with Extended Back Cover). Batteries use Hyperion Accessories "A" Grade Lithium Ion Cells. Designed and Manufactured by Hyperion Electronics Accessories. All batteries come with a 3 month manufacturers comprehensive warranty.