I have a slight clamp addiction, and when these first came out I was "talked" into trying a set by a glowing review in a woodworking magazine. Since the purchase two of the four have jammed shut so you can not open them. The company would fix them, as long as I pay the $50 shipping fee to send them to them. I have had 10 sets of Bessey parallel bar clamps, ranging up to 10 years old, and not one has ever malfunctioned or broken. Stick with the Besseys, or maybe try the jet bar clamps.