8-242 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 3.984 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
242
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
4 inch
Nominal Outside Diameter
4 1/4 inch
Unit of Measure
EA
SKU:
VBU90242
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Product Specification

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The VBU90242 is an AS568-242 black Viton® (FKM) 90 Shore A Back-Up Ring built to an inside diameter of 3.984 in (101.19 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.262 in (108.25 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Viton® (FKM) is widely chosen for excellent resistance to compression set and permeation, very low compression set at elevated temperature. The compound resists petroleum oils and fuels, engine and transmission fluids, and aromatic hydrocarbons. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). Verify compatibility before use with hot water and steam or amines.

Typical settings include oil and gas, chemical processing, and high-temperature process equipment.

This item is sold individually under part number VBU90242. Unit weight is approximately 1.967 g and nominal inside diameter is listed as 4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Item
VBU90242
Description
8-242 BLACK FKM 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
3.984 inch (101.19 mm)
Actual Outside Diameter
4.262 inch (108.25 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings