8-343 BLACK FKM 90D BACK-UP RING

VBU90343 is an AS568-343 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 3.725 in (94.62 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.145 in (105.28 mm). In service, this back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Viton® (FKM) is known for the industry benchmark where nitrile reaches its thermal limit and very low compression set at elevated temperature. The compound resists petroleum oils and fuels, many acids, and aggressive chemicals. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C). It is not the right choice where ketones and esters or low-molecular-weight organic acids are present.

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

Stocked as VBU90343 and sold individually. Unit weight is approximately 4.3271 g. As always, verify media compatibility and operating conditions against the requirements of your specific application.