O-ring, imperial, polyurethane, black, 90A shore, 2-009, 1.78 x 5.28 mm, Dichto.

An O-ring, also known as a packing, is a mechanical gasket. it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface. The O-ring may be used in static applications or in 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. Polyurethane O-rings are ideal for applications that need rubber- or plastic-characteristics, but with the durability to survive challenging environments that these materials could not. They exhibit excellent abrasion resistance, chemical resistance, elasticity, and rebound. Polyurethane is also highly resistant to abrasion, cuts, cracking, high impact, and heavy loads.