8-366 BLACK BUNA 90D BACK-UP RING

Part number HB90366 is an AS568-366 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 7.225 in (183.52 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 7.645 in (194.18 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) is valued for strong abrasion and tear resistance, the most widely specified general-purpose sealing elastomer. It resists hydraulic fluids, petroleum-based oils, and greases and lubricants. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with strong acids or ketones.

Maintenance and OEM teams specify it across construction equipment, agricultural equipment, and general industrial maintenance.

Stocked as HB90366 and sold individually. Unit weight is approximately 6.1347 g and nominal inside diameter is listed as 7 1/4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.