8-233 BLACK BUNA 90D BACK-UP RING

The HB90233 is an AS568-233 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 2.859 in (72.62 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.137 in (79.68 mm). This back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Buna-N (Nitrile) is widely chosen for reliable performance in both static and dynamic service, low compression set under sustained load. Expect good resistance to propane and butane, greases and lubricants, and petroleum-based oils. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C).

It sees regular use in automotive, general industrial maintenance, and hydraulic and pneumatic systems.

Stocked as HB90233 and sold individually. Unit weight is approximately 1.1188 g and nominal inside diameter is listed as 2 7/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.