Part number VBU90373 is an AS568-373 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 8.975 in (227.97 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 9.395 in (238.63 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
The material holds up against aggressive chemicals, petroleum oils and fuels, and aromatic hydrocarbons. Viton® (FKM) is widely chosen for excellent resistance to compression set and permeation, long service life in hot, chemically aggressive environments. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). Verify compatibility before use with ketones and esters or amines.
Maintenance and OEM teams specify it across chemical processing, automotive fuel systems, and semiconductor equipment.
Order part number VBU90373, sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Description 8-373 BLACK FKM 90D BACK-UP RING
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 8.975 inch (227.97 mm)
Actual Outside Diameter 9.395 inch (238.63 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings