This is a USB Jig.
A very useful thing if you are going to root or going to be flashing custom ROM's. It can be used to force a bricked/semi-bricked GS2 into download mode, it can clear your flash counter if the phone has to be returned for warranty and finally it can be used to remove what some people deem the ugly yellow triangle after rooting your phone.
A USB Jig can be used on a number of Samsung devices and for a few pounds/dollars it's well worth investing in if you're gong to be rooting or flashing your phone.
Swyped from a distant star, the other side of the Galaxy on my GT-I9100 powered by V3TR3MA ROM using Tapatalk ©