This application uses iPhone 4 LED light to lighten your way.In addition to other flashlight apps, this app “Flashlight Hero” has good features which are,

+ it can show how much power is consumped
+ it can show the temperature increase of your phone
+ it can save the sessions so that you can get info about power consumption of using LED.
+ it launches so quickly (2 sec.)
+ Retina display ready
+ Fast app switching

*** DISCLAIMER ***
Continued use of the flash may dramatically decrease battery life.