Bellows are used in a broad range of applications to absorb thermal movement and vibrations in pumps, tanks, pipework, turbines, and other equipment. Bellows have become very popular in engine exhaust systems, flow-lines, process lines, propulsion systems, valve systems, and different kinds of pipework. A bellow is a length of pipe with a sequence of convolutions that lets the pipe to move with one, two or three planes of movement. This is the reason the design and manufacture of bellow units are a specialized area and also requires advanced engineering. The most common form of movement provided by bellows in the axial movement. This is also called the dimensional lengthening or shortening of an expansion joint throughout its longitudinal axis. This is where a bellows expands or contracts along the length.