4.5MM CS X 21MM ID BLACK BUNA 70D

Buna-N O-Ring, 4.5 x 21 mm, 70A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Durometer
70 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Unit of Measure
EA
SKU:
H4.5X21
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Product Specification

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Part number H4.5X21 is a black Buna-N (Nitrile) 70 Shore A O-Ring with an inside diameter of 21 mm (0.827 in), a cross section of 4.5 mm (0.177 in), and an outside diameter of 30 mm (1.18 in). An o-ring creates a positive seal at flange, piston and rod interfaces without added hardware.

Buna-N (Nitrile) is widely chosen for low compression set under sustained load and the most widely specified general-purpose sealing elastomer. The compound resists water, many alcohols, and propane and butane. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving automotive brake fluid or ketones call for a different compound.

You will find this material specified across automotive, construction equipment, and general industrial maintenance.

This item is sold individually under part number H4.5X21. Check the compound against your process media, pressure and temperature before committing to a design.
Item
H4.5X21
Description
4.5MM CS X 21MM ID BLACK BUNA 70D
Actual Outside Diameter
30 mm (1.18 inch)
Actual Cross Section
4.5 mm (0.177 inch)
Actual Inside Diameter
21 mm (0.827 inch)
FDA Compliant
No
Measurement System
Metric
Metal Detectable
No
NSF Certified
No
Product Code
6015
Product Category
O-Rings - Metric - Commodity