O-ring seals, also called O-ring seals, are one of the most common and versatile sealing elements used in a variety of technical applications. O-rings are made of flexible materials such as rubber (most often nitrile, silicone, fluoro-rubber), as well as plastics or metal, and provide effective sealing in static and dynamic connections. O-rings have the shape of a ring that is placed in an appropriate grooved or crimped slot, where it is compressed as a result of squeezing the connecting surfaces, which ensures tightness.