A Structural pipe fitting, also known as a slip on pipe fitting, clamp or pipe clamp is used to build structures such as handrails, guardrails, and other types of pipe or tubular structure. They can also be used to build furniture and theatrical riggings. The fittings slip on the pipe and are usually locked down with a set screw. The set screw can then be tightened with a simple hex wench. Because of the modular design of standard fittings, assembly is easy, only simple hand tools are required, and risks from welding a structure are eliminated.