8-171 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90171, an AS568-171 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 7.987 in (202.87 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.193 in (208.1 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The material holds up against greases and lubricants, propane and butane, and many alcohols. That behavior comes from the compound itself: Buna-N (Nitrile) offers strong abrasion and tear resistance, reliable performance in both static and dynamic service. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It should not be specified for service in ozone and direct sunlight or strong acids.

Common environments for this compound include general industrial maintenance, fluid power, and construction equipment.

Stocked as HB90171 and sold individually. Unit weight is approximately 2.28 g and nominal inside diameter is listed as 8 inch. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.