Samsung 1300 mAh Extended Battery Power Pack for Samsung Galaxy S II Rechargable battery with 1300mAh capacty Stand by up to 309h (2G) / Up to 250h (3G) Talk Time Up to 557m (2G) / Up to 22m (3G) 100% Genuine Samsung Product, or your money back Fits around the Galaxy S II as a protective case and power pack.