8-239 BLACK BUNA 90D BACK-UP RING

This back-up ring is supplied in AS568-239 black Buna-N (Nitrile) 90 Shore A supplied with an inside diameter of 3.609 in (91.67 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.887 in (98.73 mm), catalogued under part number HB90239. It allows a standard o-ring to operate at higher pressures than it could unsupported.

Buna-N (Nitrile) offers the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. Expect good resistance to greases and lubricants, water, and many alcohols. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Exposure to polar solvents or automotive brake fluid will shorten service life.

It sees regular use in construction equipment, hydraulic and pneumatic systems, and general industrial maintenance.

HB90239 ships individually. Unit weight is approximately 1.3372 g. Application requirements vary, so validate compatibility with your process conditions prior to installation.