8-357 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90357, an AS568-357 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 5.475 in (139.07 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.895 in (149.73 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Viton® (FKM) is specified for outstanding high-temperature capability and very low compression set at elevated temperature. Expect good resistance to aggressive chemicals, petroleum oils and fuels, and many acids. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). It is not the right choice where low-molecular-weight organic acids or amines are present.

Maintenance and OEM teams specify it across high-temperature process equipment, oil and gas, and semiconductor equipment.

Order part number VBU90357, sold individually. Unit weight is approximately 6.78 g and nominal inside diameter is listed as 5 1/2 inch. Review your operating media and conditions against this specification before installation. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.