8-235 BLACK FKM 90D BACK-UP RING

VBU90235 is an AS568-235 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 3.109 in (78.97 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.387 in (86.03 mm). In service, this back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

It resists aggressive chemicals, aromatic hydrocarbons, and chlorinated solvents. Viton® (FKM) delivers very low compression set at elevated temperature, excellent resistance to compression set and permeation. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C).

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

Stocked as VBU90235 and sold individually. Unit weight is approximately 1.573 g and nominal inside diameter is listed as 3 1/8 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.