This repair replaces a battery installed last year that has been nothing but trouble. I chose iFixit based on reviews I found online. The original Apple battery became unreliable 2 years ago, so I purchased a replacement from a well-know large retail chain. When the replacement failed, I requested warranty replacement from the vendor only to find they would not replace it unless I returned it to them for inspection. That was not a cost-effective option, so I turned to iFixit...
Everything went perfectly. The battery was a perfect fit and electrical connection was solid. I have no complaints. The phone performs as well as it did on the very first day. Take that, Apple!
I highly recommend this iFixit 4S replacement battery and will definitely buy again.