8-388 BLACK BUNA 90D BACK-UP RING

The HB90388 is an AS568-388 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 18.953 in (481.41 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 19.373 in (492.07 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Buna-N (Nitrile) is specified for an economical choice for high-volume maintenance programs and low compression set under sustained load. This material stands up to hydraulic fluids, many alcohols, and water. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C).

Common environments for this compound include automotive, hydraulic and pneumatic systems, and fluid power.

Stocked as HB90388 and sold individually. Unit weight is approximately 15.957 g and nominal inside diameter is listed as 19 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.