Since the phone my wife is always out quickly (because they phoned so incredibly much), I've given her this spare battery. It fits perfectly into any pocket and charges your iPhone 4S loose 2x. The LED display shows then 1 light (4) = 25%, but then you load yes dear again ... Particularly advantageously, I find that the device is not as big, but small and handy. If you press the power button for 3 sec. Is the built-in torch on / off. This is not a "spotlight" but perfectly adequate for footwells in the car etc.. Conclusion: enough power while handy - very recommendable!