8-390 BLACK FKM 90D BACK-UP RING

Part number VBU90390 is an AS568-390 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 20.953 in (532.21 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 21.373 in (542.87 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

As a material, Viton® (FKM) is widely chosen for outstanding high-temperature capability and long service life in hot, chemically aggressive environments. This material stands up to aromatic hydrocarbons, aggressive chemicals, and chlorinated solvents. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C).

It sees regular use in automotive fuel systems, aerospace, and semiconductor equipment.

Reference part number VBU90390 when ordering; the item is sold individually. Nominal inside diameter is listed as 21 inch. Review your operating media and conditions against this specification before installation.