MiLi Power Spring 4 External Battery Pack for iPhone 4S / 4 - 1600mAh
Apple iPhone 4S Battery Replacement Kit with Tools, Video Instructions, Extended Life Battery and Full One Year Warranty - Walmart.com
How To: Replace the Battery on your iPhone 4s! - YouTube
Original Battery 4s for Apple iPhone 4S A1431, A1387, A1387 Mobile Battery with 6 Month Warranty and high Capacity Battery Backup.Carefully Check Your Phone Model and Purchase. (for iPhone 4s) : Amazon.in:
mophie Juice Pack Plus Battery Case for iPhone 4/4S - Black - Walmart.com
Looking inside an iPhone 4/4S battery | Rip It Apart - Jason's electronics blog-thingy
Teardown of Apple's iPhone 4S reveals larger battery, new baseband chip | AppleInsider