8-320 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90320, an AS568-320 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 1.1 in (27.94 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.52 in (38.61 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

As a material, Buna-N (Nitrile) offers reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. Expect good resistance to water, petroleum-based oils, and propane and butane. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with strong acids or ketones.

You will find this material specified across construction equipment, fluid power, and hydraulic and pneumatic systems.

Order part number HB90320, sold individually. Unit weight is approximately 1.1117 g. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.