8-018 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90018, an AS568-018 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 0.739 in (18.77 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 0.879 in (22.33 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The compound resists aromatic hydrocarbons, many acids, and petroleum oils and fuels. Viton® (FKM) delivers outstanding high-temperature capability and 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). Applications involving ketones and esters or amines call for a different compound.

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

VBU90018 ships individually. Unit weight is approximately 0.205 g and nominal inside diameter is listed as 3/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.