8-145 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 2.55 in ID x 0.103 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
145
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
3/32 inch
Nominal Inside Diameter
2 9/16 inch
Nominal Outside Diameter
2 3/4 inch
Unit of Measure
EA
SKU:
HB90145
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Product Specification

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This back-up ring is supplied in AS568-145 black Buna-N (Nitrile) 90 Shore A measuring an inside diameter of 2.55 in (64.77 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.756 in (70 mm), catalogued under part number HB90145. It allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Buna-N (Nitrile) is widely chosen for the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. It resists propane and butane, many alcohols, and hydraulic fluids. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It should not be specified for service in automotive brake fluid or strong acids.

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

HB90145 ships individually. Unit weight is approximately 0.7525 g and nominal inside diameter is listed as 2 9/16 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
Item
HB90145
Description
8-145 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.103 inch (2.62 mm)
Actual Inside Diameter
2.55 inch (64.77 mm)
Actual Outside Diameter
2.756 inch (70 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings