8-268 BLACK BUNA 90D BACK-UP RING

The HB90268 is an AS568-268 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 8.484 in (215.49 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 8.762 in (222.55 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Buna-N (Nitrile) delivers low compression set under sustained load and an economical choice for high-volume maintenance programs. The compound resists propane and butane, petroleum-based oils, and hydraulic fluids. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Exposure to ketones or polar solvents will shorten service life.

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

This item is sold individually under part number HB90268. Unit weight is approximately 3.144 g and nominal inside diameter is listed as 8 1/2 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.