8-244 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90244, an AS568-244 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 4.234 in (107.54 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.512 in (114.6 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, low compression set under sustained load. The material holds up against greases and lubricants, many alcohols, and water. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ozone and direct sunlight or ketones.

Typical settings include agricultural equipment, construction equipment, and hydraulic and pneumatic systems.

Stocked as HB90244 and sold individually. Unit weight is approximately 1.5969 g. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.