A pipe coupling is any fitting or device used to join two or more pipes in such a way that continuity is maintained between them. The body of a pipe coupling is typically made of the same or similar materials as those used to construct the pipes it joins. They may be rigid or flexible depending on the amount of movement the pipe is subjected to and may per permanent or removable fixtures. A pipe coupling can be stepped or reduced in internal diameter to accept pipes of different sizes, be T or cross shaped to join more than two pipes, or angled to form bends. Pipe couplings may also include peripheral features or equipment such as inspection openings, flow meters, or valves.