TheKupo 4″ Steel Spring A Clampis one of the most useful tools on film or photo sets. The Spring Clamp is also known as an A clamp. Constructed from solid steel with PVC coated handle and tips, features spring-operated pincers which allows a quick and easy mounting solution for many lightweight attachment needs. It is great for clipping a reflector or bounce card to a stand, or to keep a roll of seamless paper from unrolling.