8-353 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 4.975 in ID x 0.21 CS, 90A, Black, -15 to 400°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Fluoroelastomer (FKM/Viton)
Dash Size
353
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
5 inch
Nominal Outside Diameter
5 3/8 inch
Unit of Measure
EA
SKU:
VBU90353
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Product Specification

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VBU90353 is an AS568-353 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 4.975 in (126.37 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.395 in (137.03 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

This material stands up to chlorinated solvents, petroleum oils and fuels, and aggressive chemicals. Viton® (FKM) is widely chosen for the industry benchmark where nitrile reaches its thermal limit and very low compression set at elevated temperature. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C). It is not the right choice where amines or ketones and esters are present.

Common environments for this compound include oil and gas, chemical processing, and high-temperature process equipment.

VBU90353 ships individually. Unit weight is approximately 5.771 g and nominal inside diameter is listed as 5 inch. Review your operating media and conditions against this specification before installation.
Item
VBU90353
Description
8-353 BLACK FKM 90D BACK-UP RING
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
4.975 inch (126.37 mm)
Actual Outside Diameter
5.395 inch (137.03 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings