8-223 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90223, an AS568-223 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 1.609 in (40.87 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.887 in (47.93 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 low compression set under sustained load and most widely specified general-purpose sealing elastomer. The material holds up against propane and butane, hydraulic fluids, and petroleum-based oils. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in ozone and direct sunlight or strong acids.

Maintenance and OEM teams specify it across general industrial maintenance, fluid power, and construction equipment.

Reference part number HB90223 when ordering; the item is sold individually. Unit weight is approximately 0.6456 g and nominal inside diameter is listed as 1 5/8 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.