8-379 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90379, an AS568-379 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 10.975 in (278.77 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 11.395 in (289.43 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

The compound resists petroleum oils and fuels, many acids, and engine and transmission fluids. That behavior comes from the compound itself: Viton® (FKM) is known for long service life in hot, chemically aggressive environments, excellent resistance to compression set and permeation. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C).

You will find this material specified across oil and gas, automotive fuel systems, and chemical processing.

This item is sold individually under part number VBU90379. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.