O-ring is a rubber seal with a circular cross section. Because its cross section is O-shaped, it is called O-ring seal ring, also called O-ring.
Because of its low cost, simple manufacturing, reliable functionality, and simple installation requirements, O-rings are the most common mechanical design for sealing. O-rings are subjected to pressures of tens of megapascals (thousand pounds). O-rings can be used in static applications or in dynamic applications where there is relative motion between components, such as rotary pump shafts and hydraulic cylinder pistons.