NewerTech® : Batteries : NuPower® Battery Replacement Service for Apple® iPhone® 3GS
I was planning to use my old iPhone 3GS for weekend project but I discovered that the screen was popped out and the back was bulging, I took it apart and this
my iPhone 3GS Battery started expanding and it popped the screen off : r/techsupportgore
Source For iPhone 3GS OEM Replacement Battery 1220mAh 616-0431 616-0433 616-0435 on m.alibaba.com
iPhone 3GS Battery Problems - Read This Before You Replace It! — navigate