I love this hoop,now. At first I had atrouble with it. The very first time I used it that little tightening handle came off and I couldn't figure out how to get it back on so just left it off. If you look at the screw there is a slot in the side that you can slip a screwdriver and turn to tighten it but I usually just twist it by hand and it stays okay. Also follow clawton's excellent tips.
I also have trouble sometimes with it. Be sure to have it on a solid surface before clamping it. I think if you have it set to loose it pops out. It is hard to decide how tight to make it. I'm afraid I'll break it. It cost too much to buy another one. Once I get it set to where it works well I try not to let the clamp part not twist around to a different setting while re-hooping.