8-377 BLACK FKM 90D BACK-UP RING

The VBU90377 is an AS568-377 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 9.975 in (253.37 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 10.395 in (264.03 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Viton® (FKM) is widely chosen for the industry benchmark where nitrile reaches its thermal limit and long service life in hot, chemically aggressive environments. It resists many acids, 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 is not the right choice where low-molecular-weight organic acids or hot water and steam are present.

It sees regular use in aerospace, high-temperature process equipment, and automotive fuel systems.

Stocked as VBU90377 and sold individually. Review your operating media and conditions against this specification before installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.