AS568-243 Buna-N 70 Duro Black O-Ring for 4-1/8 ID X 1/8 CS

Buna-N O-Rings 70 Duro Black BN700100-243

$ 0.4912 per Each

Minimum Order Quantity (MOQ): 62

Ships within 7 days

Qty	Price
62 - 71	$0.4912
72 - 152	$0.3684
153 - 305	$0.2947
306 - 610	$0.2210
611+	$0.1805

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Product Details

Material	Buna-N
Temperature Range	-40°F to 250°F
Cross Sectional Shape	Round
Hardness	70
Dash	243
Fractional	ID: 4-1/8 CS: 1/8 OD: 4-3/8
Actual (Inch)	ID: 4.109 ± 0.028 CS: 0.139 ± 0.004 OD: 4.387
Actual (Metric)	ID: 104.37 ± 0.71 CS: 3.53 ± 0.10 OD: 111.430

Buna-N (Nitrile) O-rings are made from a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. They are among the most widely used sealing materials due to their excellent resistance to oils, fuels, and many chemicals. Nitrile O-rings provide high mechanical strength, outstanding wear resistance, and good tensile strength, making them ideal for automotive, industrial, and aerospace applications.

Buna-N Recommended Uses

Seals and gaskets, fuel systems, hydraulic systems, oil and gas industry, automotive applications, general-purpose applications.

Buna-N Not Recommended

Brake fluid, ozone, UV exposure, phosphate esters, chlorinated hydrocarbons, aromatic hydrocarbons, ketones, strong acids, atmospheric aging.

Buna-N Limitations

Not suitable for ozone, sunlight, or weathering exposure.
Limited performance in high-temperature environmen.
Not ideal for strong acids and alkalis.
Not recommended for applications requiring low compression set.

Buna-N Usable Temperature Range

-30 to 250°F (-34 to 121°C)

Buna-N Also Known As

Buna-N, Nitrile, NBR, Nitrile Butadiene Rubber.