8-107 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90107, an AS568-107 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 0.206 in (5.23 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 0.412 in (10.46 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The compound resists aromatic hydrocarbons, engine and transmission fluids, and chlorinated solvents. That behavior comes from the compound itself: Viton® (FKM) is valued for outstanding high-temperature capability and the industry benchmark where nitrile reaches its thermal limit. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). Applications involving amines or hot water and steam call for a different compound.

Maintenance and OEM teams specify it across automotive fuel systems, aerospace, and oil and gas.

VBU90107 ships individually. Nominal inside diameter is listed as 7/32 inch. Review your operating media and conditions against this specification before installation.