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8-373 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 8.975 in ID x 0.21 CS, 90A, Black, -15 to 400°F

Status
Out of Stock
Est. Ship Date
21 Oct 2026
Material
Fluoroelastomer (FKM/Viton)
Dash Size
373
Durometer
90 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-15°F (-26°C)
Maximum Temperature
400°F (204°C)
Nominal Cross Section
3/16 inch
Nominal Inside Diameter
9 inch
Nominal Outside Diameter
9 3/8 inch
Unit of Measure
EA
SKU:
VBU90373

Product Specification

-
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.
Item
VBU90373
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)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings