8-243 BLACK BUNA 90D BACK-UP RING

Ordered as HB90243, this is an AS568-243 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 4.109 in (104.37 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.387 in (111.43 mm). The 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, strong abrasion and tear resistance. This material stands up to hydraulic fluids, petroleum-based oils, and greases and lubricants. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C).

Common environments for this compound include hydraulic and pneumatic systems, agricultural equipment, and general industrial maintenance.

Stocked as HB90243 and sold individually. Unit weight is approximately 1.5277 g and nominal inside diameter is listed as 4 1/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.