8-138 BLACK FKM 90D BACK-UP RING

VBU90138 is an AS568-138 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 2.112 in (53.64 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.318 in (58.88 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Expect good resistance to chlorinated solvents, many acids, and petroleum oils and fuels. Viton® (FKM) offers excellent resistance to compression set and permeation, very low compression set at elevated temperature. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with low-molecular-weight organic acids or ketones and esters.

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

Reference part number VBU90138 when ordering; the item is sold individually. Unit weight is approximately 0.847 g and nominal inside diameter is listed as 2 1/8 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.