Upgrade via replacement. We wouldn"t give you anything less than the best. Grade A cells chosen from among the top 10%. Rigorous inspection tests to ensure reliability. A built-in IC chip to prevent against short-circuiting. Complete NFC functionality. What does this all mean? In terms of quality, you won"t find a better replacement. Don"t just take our word for it, though - type in any quick, power-related search on Amazon and see who pops up. As the leader in our industry for the last 3 years running, we know batteries. Get to know us. Here at Anker, we"re dedicated to making the smart life easier. As a Top Rated Brand on Amazon, we"ve established ourselves as a leader in the field, bringing innovative and reliable technological solutions to millions of users across the globe. Our Astro line of external batteries has been voted #1 in class by thousands of online reviewers and praised by tech bloggers, while our renowned customer service team has made us a fan-favorite across the web. With every sale, we include an 18-month, worry-free guarantee to demonstrate the importance we set on quality. After all, we"re customers too. Compatible Models: Samsung Galaxy S4, S IV, GT-I9505, GT-I9500, Galaxy S4 LTE I9506, Galaxy J, SGH-M919 (T-Mobile), SCH-I545 (Verizon), SGH-I337 (AT&T), SPH-L720 (Sprint), SCH-R970 (U.S. Cellular/MetroPCS) Not for Galaxy S4 Active