8-464 BLACK BUNA 90D BACK-UP RING

Ordered as HB90464, this is an AS568-464 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 17.455 in (443.36 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 18.005 in (457.33 mm). The back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

The material holds up against greases and lubricants, petroleum-based oils, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) is known for the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where polar solvents or automotive brake fluid are present.

Maintenance and OEM teams specify it across fluid power, construction equipment, and agricultural equipment.

This item is sold individually under part number HB90464. Unit weight is approximately 30.51 g and nominal inside diameter is listed as 17 1/2 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.