8-366 BLACK FKM 90D BACK-UP RING

The VBU90366 is an AS568-366 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 7.225 in (183.52 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 7.645 in (194.18 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Expect good resistance to aromatic hydrocarbons, chlorinated solvents, and petroleum oils and fuels. That behavior comes from the compound itself: Viton® (FKM) is known for the industry benchmark where nitrile reaches its thermal limit and long service life in hot, chemically aggressive environments. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). It should not be specified for service in low-molecular-weight organic acids or amines.

Common environments for this compound include oil and gas, chemical processing, and high-temperature process equipment.

Stocked as VBU90366 and sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.