8-338 BLACK BUNA 90D BACK-UP RING

The HB90338 is an AS568-338 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 3.1 in (78.74 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 3.52 in (89.41 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

It resists many alcohols, hydraulic fluids, and water. Buna-N (Nitrile) is valued for the most widely specified general-purpose sealing elastomer, reliable performance in both static and dynamic service. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in automotive brake fluid or ozone and direct sunlight.

It sees regular use in agricultural equipment, construction equipment, and hydraulic and pneumatic systems.

Reference part number HB90338 when ordering; the item is sold individually. Unit weight is approximately 2.718 g. As always, verify media compatibility and operating conditions against the requirements of your specific application.