8-221 BLACK BUNA 90D BACK-UP RING

Ordered as HB90221, this is an AS568-221 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 1.421 in (36.09 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.699 in (43.15 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) is known for an economical choice for high-volume maintenance programs and the most widely specified general-purpose sealing elastomer. The material holds up against hydraulic fluids, petroleum-based oils, and water. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where ketones or strong acids are present.

Typical settings include automotive, construction equipment, and agricultural equipment.

Stocked as HB90221 and sold individually. Unit weight is approximately 0.5675 g and nominal inside diameter is listed as 1 7/16 inch. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.