It will let you know exactly how much longer your battery will last while you perform any of the following: playing 3D games, 2D games, talking on the phone, surfing using 3G, using WiFi, playing videos or audio files, or just doing nothing. The app will also tell you how long it will take to completely charge your phone.
In addition, you can also change the appearance of the battery bar to suit your tastes, although this is an insignificant detail.
Battery Magic is a rather useful tool for users planning on taking long trips, or who won't be able to recharge their phone for a while, since it tells them exactly how long their battery will last.
Compatible with iPhone, iPod touch, and iPad.