8-323 BLACK FKM 90D BACK-UP RING

Part number VBU90323 is an AS568-323 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 1.287 in (32.69 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.707 in (43.36 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

This material stands up to many acids, chlorinated solvents, and engine and transmission fluids. That behavior comes from the compound itself: Viton® (FKM) is valued for the industry benchmark where nitrile reaches its thermal limit, excellent resistance to compression set and permeation. The material carries a published service range of -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.

Common environments for this compound include oil and gas, automotive fuel systems, and semiconductor equipment.

This item is sold individually under part number VBU90323. Nominal inside diameter is listed as 1 5/16 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.