The cross clamp is used to connect two hexagonal tubes at 90-degree angles (for example to connect a leg tube with a tube that has been horizontally set). With a synthetic sleeve HexRackII clamps get a rock solid grip on the rails. As the clamp tightens it compresses the sleeve to establish a solid grip. This gives the clamp a secure slip-free hold on the rail when tightened and allows easy adjustment when loosened making the whole setup process quick easy flexible and solid.