8-108 BLACK BUNA 90D BACK-UP RING

Ordered as HB90108, this is an AS568-108 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 0.237 in (6.02 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 0.443 in (11.25 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

It resists petroleum-based oils, propane and butane, and many alcohols. Buna-N (Nitrile) offers reliable performance in both static and dynamic service, an economical choice for high-volume maintenance programs. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with automotive brake fluid or strong acids.

Typical settings include hydraulic and pneumatic systems, agricultural equipment, and general industrial maintenance.

Order part number HB90108, sold individually. Unit weight is approximately 0.097 g and nominal inside diameter is listed as 1/4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.