-203 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90203, an AS568-203 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 0.296 in (7.52 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.574 in (14.58 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, low compression set under sustained load. It resists greases and lubricants, hydraulic fluids, and water. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or automotive brake fluid.

Common environments for this compound include automotive, construction equipment, and agricultural equipment.

HB90203 ships individually. Unit weight is approximately 0.16 g and nominal inside diameter is listed as 5/16 inch. Check the compound against your process media, pressure and temperature before committing to a design.