8-380 BLACK BUNA 90D BACK-UP RING

HB90380 is an AS568-380 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 11.475 in (291.47 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 11.895 in (302.13 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Buna-N (Nitrile) is specified here for low compression set under sustained load, strong abrasion and tear resistance. This material stands up to propane and butane, many alcohols, and hydraulic fluids. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). It is not the right choice where strong acids or ketones are present.

Maintenance and OEM teams specify it across general industrial maintenance, fluid power, and automotive.

Reference part number HB90380 when ordering; the item is sold individually. Unit weight is approximately 9.606 g and nominal inside diameter is listed as 11 1/2 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.