8-341 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 3.475 in ID x 0.21 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
341
Durometer
90 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Nominal Cross Section
3/16 inch
Nominal Inside Diameter
3 1/2 inch
Nominal Outside Diameter
3 7/8 inch
Unit of Measure
EA
SKU:
HB90341
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Product Specification

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Part number HB90341 is an AS568-341 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 3.475 in (88.27 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 3.895 in (98.93 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Buna-N (Nitrile) is specified for reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. This material stands up to water, propane and butane, and petroleum-based oils. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C).

Common environments for this compound include general industrial maintenance, construction equipment, and fluid power.

This item is sold individually under part number HB90341. Unit weight is approximately 3.1373 g and nominal inside diameter is listed as 3 1/2 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
HB90341
Description
8-341 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
3.475 inch (88.27 mm)
Actual Outside Diameter
3.895 inch (98.93 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings