The O-ring is the most widely used seal in the industry. It is easy to install, may be used as a double-acting seal and can seal pressures of up to 800 PSI. The o-ring is typically used as a reciprocating seal, not for rotating shaft applications (lip seals should be used for rotating shafts). O-rings are typically sized by their inside diameter and cross section, and are further specified by the type of compound used. For a better description of materials see our material guide.