-255 BLACK BUNA 70D O-RING

Buna-N O-Ring, 5.609 in ID x 0.139 CS, 70A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
255
Durometer
70 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Nominal Cross Section
1/8 inch
Nominal Inside Diameter
5 5/8 inch
Nominal Outside Diameter
5 7/8 inch
Unit of Measure
EA
SKU:
H70255
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Product Specification

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This o-ring is supplied in AS568-255 black Buna-N (Nitrile) 70 Shore A supplied with an inside diameter of 5.609 in (142.47 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.887 in (149.53 mm), catalogued under part number H70255. It creates a positive seal at flange, piston and rod interfaces without added hardware.

Expect good resistance to hydraulic fluids, greases and lubricants, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) offers strong abrasion and tear resistance, low compression set under sustained load. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving ketones or ozone and direct sunlight call for a different compound.

Common environments for this compound include fluid power, construction equipment, and agricultural equipment.

Stocked as H70255 and sold individually. Unit weight is approximately 5.512 g and nominal inside diameter is listed as 5 5/8 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.
Item
H70255
Description
-255 BLACK BUNA 70D O-RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
5.609 inch (142.47 mm)
Actual Outside Diameter
5.887 inch (149.53 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6005
Product Category
O-Rings - Bulk - Commodity