These clamps were designed for woodworking to aid in corner joints. The clamps have a spring loaded mechanism which I find very difficult to open. The clamps are not strong enough to hold the wood in place for much play. Clamps must fit different sizes; However, if you get too big, it won't work, and if you get too small, you'll have a lot of problems. They didn't come with instructions on how to do it, and they have a few spaces that don't work either. This product is not for me and it hurts more than it helps.