Unlocked Iphone 1st Gen. battery kept dying.
The battery would go from 100 to 50 to dead in a 5 min. phone call.
It took 15 minute to change it out. Super easy. The phone is working like a charm now. full charge. the battery never dies. like a brand new phone!
Don't be intimidated by the reviews. It's very simple process. does't take 45 min! and it can save you a lot of money of replacing your phone. fix it, don't buy another!