Own a iPhone 4S for long time, but i carelessly dropped my 4s into water and the stock battery stopped working. I didn't know how to fix it though I've tried drying it with a hair dryer and even putting in rice but it did not work, so i had to consider it as a totally died one. Since I prefer to try myself to replace the battery with screwdriver rather to wait long time, so after comparing prices and discounts I bought a new replacement battery from MPJ, cost much lower than in apple shop and have used it for a few days already. It appears to work just as well as the stock 4s battery. I don't know its actual longevity but it works OK so far. Success!