This replacement battery for your iPhone 4G is a perfect choice for you if your iPhone battery is old, weak or broken, or you just want keep you contacted or the music playing on your Apple iPhone. Instructions: We recommend a full charge of at least 10 hours before the first use. This will ensure that the battery will always charge to its maximum load. Please note battery life is dependent on how much you use your phone, running many applications, using bluetooth, playing music and videos will use a lot of battery power. WARNING: To reduce risk of fire or burns, do not disassemble, crush, puncture short external contacts, or dispose of in fire or water.If you need the battery for iphone 5s, please search "B00JEXLUGC", If you need the battery for iphone 5c, please search "B00JEXXVZA".