8-344 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90344, an AS568-344 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 3.85 in (97.79 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.27 in (108.46 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Buna-N (Nitrile) is valued for the most widely specified general-purpose sealing elastomer and low compression set under sustained load. It resists petroleum-based oils, hydraulic fluids, and greases and lubricants. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C).

Common environments for this compound include hydraulic and pneumatic systems, fluid power, and general industrial maintenance.

Stocked as HB90344 and sold individually. Unit weight is approximately 3.4113 g and nominal inside diameter is listed as 3 7/8 inch. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.