A circlip (a portmanteau of "circle" and "clip"), also known as a C-clip, Rotor Clip, snap ring or Jesus clip,[1] is a type of fastener or retaining ring consisting of a semi-flexible metal ring with open ends which can be snapped into place, into a machined groove on a dowel pin or other part to permit rotation but to prevent axial movement. There are two basic types: internal and external, referring to whether they are fitted into a bore or over a shaft. Circlips are often used to secure pinned connections.
When used to retain piston wrist pins or gudgeon pins, the clips are known as wrist pin clips, wrist pin retainers, or gudgeon pin clips. The most commonly used circlip for this application is a simple spring steel circlip, or plain wire ring.
