O-ring, O-ring (O-rings) is a kind of rubber sealing ring with a circular cross section. Because of its O-shaped cross section, it is called O-ring rubber sealing ring, also called O-ring. It began to appear in the middle of the 19th century, when it was used as a sealing element for steam engine cylinders. O-rings are the most common mechanical design for seals because they are inexpensive, simple to manufacture, reliable in function, and have simple installation requirements. O-rings withstand tens of megapascals (thousands of pounds) of pressure. O-rings can be used in static applications as well as dynamic applications where there is relative motion between parts, such as shafts of rotary pumps and pistons of hydraulic cylinders.
