The tool itself suppose to help to tune intonation (length of the string) on the Floyd Rose floating bridges.
Anyways, it did not help me much. The thing is, when you tune with tension, it will hold saddle from popping out, but it is very hard to rotate the wheel for tuning and sometimes you have higher chance to break/overturn the saddle instead of just moving it, especially if you change the position of the screw for string intonation which holds the saddle from up to bottom.
Maybe some people will find it very useful - but I'd prefer to do it in old way without this tool after trying.