The clamp holder is used in conjunction with several other lab pieces to hold a container of any given substance during an experiment that often involves heating the substance. It is attached to the rod of the ring stand and is used when the ring lacks a built-in thumbscrew.
There are several other pieces of laboratory equipment that are commonly used with a clamp holder. These pieces include the ring stand, ring, clamp, wire mesh, triangular crucible holder, Bunsen burner and a scale. To use a clamp holder, tighten the thumbscrews until it is securely fastened to the ring stand.