This application was actually designed to display only a black screen on your device.Some utilities:- Save the device battery while it is not locked, like a screen saver.- Avoid unlocking the device with password several consecutive times and in a short time, just by switching between the apps;- Easily shows scratches on the screen;Some uselessness:- People bored using phones;- Fun, for example, saying that your cell phone is damaged, stuck or anything;Have fun!