حلقه چنبری

Also known as O ring, packing, toric joint, sealing ring

thumb|right|250px|Typical O-ring and application An O-ring, also known as a packing or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, forming a seal at the interface.