8-158 BLACK BUNA 90D BACK-UP RING

Part number HB90158 is an AS568-158 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 4.737 in (120.32 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.943 in (125.55 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

The compound resists water, greases and lubricants, and many alcohols. Buna-N (Nitrile) is specified for reliable performance in both static and dynamic service, low compression set under sustained load. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Exposure to ketones or polar solvents will shorten service life.

Common environments for this compound include hydraulic and pneumatic systems, fluid power, and construction equipment.

Reference part number HB90158 when ordering; the item is sold individually. Unit weight is approximately 1.389 g and nominal inside diameter is listed as 4 3/4 inch. Check the compound against your process media, pressure and temperature before committing to a design.