O-ring cross-section refers to "O" shaped rubber ring. Hydraulic and pneumatic drive system is the most widely used one. Mainly used for mechanical parts to prevent leakage of liquid and gaseous media under static conditions. In some cases, O-ring can also be used as dynamic sealing element axially reciprocating motion and low speed rotary motion. Its structure is simple, easy installation, low cost, easy maintenance, materials and diverse. It can be used as oil, water, gas and other kinds of fluid-tight seal. Depending on the conditions, different materials can be selected corresponding.

From the principle point of view seal, O-ring seal is an extrusion, extrusion seals basic working principle is to rely on the seal is elastically deformed, resulting in sealing contact with the surface of the contact pressure, the contact pressure is greater than the medium to be sealed internal pressure, no leak, otherwise leak.