8-331 BLACK BUNA 90D BACK-UP RING

The HB90331 is an AS568-331 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 2.225 in (56.52 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 2.645 in (67.18 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) is valued for strong abrasion and tear resistance, an economical choice for high-volume maintenance programs. The compound resists water, propane and butane, and greases and lubricants. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). It should not be specified for service in ozone and direct sunlight or ketones.

Typical settings include construction equipment, hydraulic and pneumatic systems, and general industrial maintenance.

Reference part number HB90331 when ordering; the item is sold individually. Unit weight is approximately 2.0331 g and nominal inside diameter is listed as 2 1/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.