8-239 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 3.609 in ID x 0.139 CS, 90A, Black, -15 to 400°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Fluoroelastomer (FKM/Viton)
Dash Size
239
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
1/8 inch
Nominal Inside Diameter
3 5/8 inch
Nominal Outside Diameter
3 7/8 inch
Unit of Measure
EA
SKU:
VBU90239
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Product Specification

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Part number VBU90239 is an AS568-239 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 3.609 in (91.67 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.887 in (98.73 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

This material stands up to many acids, aromatic hydrocarbons, and chlorinated solvents. Viton® (FKM) offers long service life in hot, chemically aggressive environments and outstanding high-temperature capability. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C).

It sees regular use in high-temperature process equipment, semiconductor equipment, and aerospace.

VBU90239 ships individually. Unit weight is approximately 1.8333 g and nominal inside diameter is listed as 3 5/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Item
VBU90239
Description
8-239 BLACK FKM 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
3.609 inch (91.67 mm)
Actual Outside Diameter
3.887 inch (98.73 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings