An O-Ring, also known as a packing, or a toric joint, is a gasket in the shape of a torus, or doughnut shape. It is a loop of elastomer with a round cross-section, designed to be seated in a groove and/or compressed during assembly between two or more parts, creating a seal. The O-Ring may be used in static or dynamic applications where there is relative motion between the parts and the O-Ring.
O-Rings are one of the most common seals used in machine design because they are inexpensive, easy to make, and reliable and have simple mounting requirements.
Highly Saturated Nitrile (HSN)
PTFE (a generic compound of Teflon™, a trademark of The Chemours Company)
PTFE Coated (PTFE coated, usually Silicone or Viton)
PTFE Encapsulated (Usually Silicone or Viton covered with a PTFE tube)
Kalrez, Chemraz, Simriz (FFKM)
Custom compounds and formulations