8-370 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90370, an AS568-370 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 8.225 in (208.92 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 8.645 in (219.58 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Viton® (FKM) is specified here for long service life in hot, chemically aggressive environments and outstanding high-temperature capability. The material holds up against petroleum oils and fuels, aggressive chemicals, and many acids. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with low-molecular-weight organic acids or amines.

Maintenance and OEM teams specify it across oil and gas, semiconductor equipment, and chemical processing.

Order part number VBU90370, sold individually. Nominal inside diameter is listed as 8 1/4 inch. Review your operating media and conditions against this specification before installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.