8-109 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90109, an AS568-109 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 0.299 in (7.59 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 0.505 in (12.83 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The material holds up against aromatic hydrocarbons, chlorinated solvents, and aggressive chemicals. That behavior comes from the compound itself: Viton® (FKM) is widely chosen for long service life in hot, chemically aggressive environments, excellent resistance to compression set and permeation. 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 hot water and steam are present.

Common environments for this compound include oil and gas, chemical processing, and automotive fuel systems.

This item is sold individually under part number VBU90109. 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.