I had never heard of one of these, but found it interesting so I made one. Took all of about 2min thanks to some strap I had with buckles already on it. I found I had great back tension right from the start. It did get my right back muscles burning after a few shots, might have been the jolt of the string catching the bow string. I had about 1.5" of slack in the string, to ensure a clean release past the fingers. I thought everybody must use their back, so I tried it on my 6yr old son with his 15lb bow. He had excellent back tension, as his draw arm didnt move any either. My question, is there any point in using this if ones form and back tension seem to be good? I didnt notice my bow arm jumping around as was mentioned above. Do you guys practice drawing your bow with just this device and not your hand? Guess I dont see the bennefit of this?