8-359 BLACK FKM 90D BACK-UP RING

APG stocks the VBU90359, an AS568-359 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 5.725 in (145.42 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 6.145 in (156.08 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The compound resists aggressive chemicals, petroleum oils and fuels, and engine and transmission fluids. That behavior comes from the compound itself: Viton® (FKM) delivers excellent resistance to compression set and permeation, very low compression set at elevated temperature. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). Verify compatibility before use with hot water and steam or ketones and esters.

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

This item is sold individually under part number VBU90359. Nominal inside diameter is listed as 5 3/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.