8-387 BLACK BUNA 90D BACK-UP RING

Part number HB90387 is an AS568-387 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 17.955 in (456.06 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 18.375 in (466.73 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) is specified here for most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. This material stands up to water, petroleum-based oils, and many alcohols. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or ketones.

You will find this material specified across general industrial maintenance, fluid power, and hydraulic and pneumatic systems.

This item is sold individually under part number HB90387. Unit weight is approximately 15.069 g and nominal inside diameter is listed as 18 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.