8-310 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 0.475 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
310
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
1/2 inch
Nominal Outside Diameter
7/8 inch
Unit of Measure
EA
SKU:
HB90310
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Product Specification

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The HB90310 is an AS568-310 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 0.475 in (12.07 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 0.895 in (22.73 mm). This back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Buna-N (Nitrile) is specified here for reliable performance in both static and dynamic service, economical choice for high-volume maintenance programs. The material holds up against petroleum-based oils, greases and lubricants, and propane and butane. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Applications involving ozone and direct sunlight or automotive brake fluid call for a different compound.

Common environments for this compound include hydraulic and pneumatic systems, automotive, and agricultural equipment.

Order part number HB90310, sold individually. Unit weight is approximately 0.588 g. Application requirements vary, so validate compatibility with your process conditions prior to installation.
Item
HB90310
Description
8-310 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
0.475 inch (12.07 mm)
Actual Outside Diameter
0.895 inch (22.73 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings