O-Rings

An O-Ring is a simple circular sealing ring with a round cross section,a torus, usually made from an elastomeric material. The O-Ring's simple design lends itself to a multitude of sealing uses, including static and reciprocal dynamic applications at low speed and low pressure, rotary and oscillating applications.

AS568A (Aerospace Size Standard for O-Rings) is generally considered to be the U.S. size standard.  Tube Fitting Bosses are included in AS568A, but are intended for use as straight thread tube fitting O-Ring gaskets.

RT/Dygert also stocks Metric and Non-Standard O-Rings.