8-168 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90168, an AS568-168 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 7.237 in (183.82 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 7.443 in (189.05 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Expect good resistance to chlorinated solvents, aromatic hydrocarbons, and many acids. That behavior comes from the compound itself: Viton® (FKM) is specified for long service life in hot, chemically aggressive environments and outstanding high-temperature capability. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C).

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

VBU90168 ships individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.