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8-203 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 0.296 in ID x 0.139 CS, 90A, Black, -15 to 400°F

Status
Out of Stock
Est. Ship Date
20 Oct 2026
Material
Fluoroelastomer (FKM/Viton)
Dash Size
203
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
5/16 inch
Nominal Outside Diameter
9/16 inch
Unit of Measure
EA
SKU:
VBU90203

Product Specification

-
APG stocks the VBU90203, an AS568-203 black Viton® (FKM) 90 Shore A Back-Up Ring supplied with an inside diameter of 0.296 in (7.52 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.574 in (14.58 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

It resists aggressive chemicals, aromatic hydrocarbons, and many acids. Viton® (FKM) is known for outstanding high-temperature capability and the industry benchmark where nitrile reaches its thermal limit. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with ketones and esters or hot water and steam.

It sees regular use in automotive fuel systems, aerospace, and semiconductor equipment.

This item is sold individually under part number VBU90203. Review your operating media and conditions against this specification before installation.
Item
VBU90203
Description
8-203 BLACK FKM 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
0.296 inch (7.52 mm)
Actual Outside Diameter
0.574 inch (14.58 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings