Either get a durable housing or with built-in battery. Or Ion that has both.
OtterBox Defender for more or less all bestselling mobiles and provides a pretty substantial protection against rough handling. Defender Ion exists so far only to Iphone 4 and 4S, but are on their way to at least the Iphone 5. In addition to the usual two-piece design in silicone and polycarbonate can be found a number of LEDs on the front and a micro-USB port at the bottom. The shell is also somewhat smaller and lighter than a regular Defender-shell, although there is an extra battery at 1 450 milliampere-hours inside the shell. The battery has probably taken place from any shock-absorbing properties, but still can withstand a lot of abuse. The battery itself can be activated by a well hidden button on the front, which also activates the LEDs to show how much battery is left. The battery is not enough really to double your phone’s lifetime, but it is convenient to have that emergency supplies after a hard day’s use.
To the shell, there is also an accompanying app that simply shows how much cream that remains in your phone and shell. More or less unnecessary, then, as the shell can already show the battery level.
Ion is a lot more expensive than their usual Defender-cousin, slightly too expensive, we think. But do you need both emergency charging that a durable housing, it is one of the few options available packaged in the same shell.
Type: Casing with built-in battery
Fits: IPhone 4/4S
Dimensions: x x 20.6 mm 130.6 68.3
Weight: 96 g
Battery: 1 450 mAh