A Polished Bed Joint Clamp is a device used in masonry construction to hold bricks or blocks in place while the martar sets. It is typically made of steel or other strong, durable material and consists of two plates that clamp together to hold the bricks or blocks in place. The Polished Bed Joint Clamp is placed on the top of the first course of bricks or blocks, with the bottom plate resting on the top of the brick or block and the top plate holding the next course of bricks or blocks in place.