The BESSEY Quick Release c-clamps have a malleable cast-iron frame with a powder coated finish. Spindle & pressure pad are chrome plated. A press of the red quick-release button allows for rapid fitting, opening and closing, to work piece when not under pressure - do not use to release a tool that is clamped onto a work piece (under pressure) as this will cause the quick release mechanism to wear out prematurely. Great for light duty, highly repetitive assembly work. BESSEY. Simply better.