This thing does exactly what you think it should do. It flips around so that you can accommodate different angles for different body sizes. A useful quality. My only complaint is that it is a bit expensive for a "thing" that you really can live without. A rolled up towel has always worked before. However, a rolled up towel doesn't always stayed rolled up nor does it always stay where you want it to stay. This thing does.
In the end, I like it. In fact, I like it a lot. Anything that takes just a bit of the labor out of string changes (I have several different types of stringed instruments and I love fresh strings) is a good thing. This is a worthwhile tool and, do not forget....it looks kinda cool too.