8-442 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90442, an AS568-442 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 7.225 in (183.52 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.775 in (197.49 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Viton® (FKM) is specified for outstanding high-temperature capability, excellent resistance to compression set and permeation. The compound resists petroleum oils and fuels, engine and transmission fluids, and chlorinated solvents. Rated temperature range runs from -15°F (-26.1°C) to 400°F (204.4°C) in continuous service. Applications involving amines or ketones and esters call for a different compound.

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

Stocked as VBU90442 and sold individually. Unit weight is approximately 17.564 g. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.