O-rings are the most widely used seal in history because of its simplicity, low cost, ease of installation and small space requirements. O-rings are designed for both static and dynamic applications. A properly designed O-ring groove allows the O-ring to be squeezed diametrically out-of-round even before the pressure is applied. The distortion of the O-ring’s resilient elastic compound fills the leakage path, thus, creating a seal.