8-250 BLACK FKM 90D BACK-UP RING

VBU90250 is an AS568-250 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 4.984 in (126.59 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.262 in (133.65 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The material holds up against engine and transmission fluids, aromatic hydrocarbons, and petroleum oils and fuels. Viton® (FKM) is widely chosen for excellent resistance to compression set and permeation, the industry benchmark where nitrile reaches its thermal limit. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). It should not be specified for service in low-molecular-weight organic acids or ketones and esters.

You will find this material specified across automotive fuel systems, high-temperature process equipment, and oil and gas.

Order part number VBU90250, sold individually. Nominal inside diameter is listed as 5 inch. 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.