AS568-355 Buna-N 70 Duro Black O-Ring for 5-1/4 ID X 3/16 CS

Buna-N O-Rings 70 Duro Black BN700100-355

$ 1.03 per Each

Minimum Order Quantity (MOQ): 30

Ships within 7 days

Qty	Price
30 - 33	$1.0300
34 - 72	$0.7725
73 - 145	$0.6180
146 - 291	$0.4635
292+	$0.3611

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Product Details

Material	Buna-N
Temperature Range	-40°F to 250°F
Cross Sectional Shape	Round
Hardness	70
Dash	355
Fractional	ID: 5-1/4 CS: 3/16 OD: 5-5/8
Actual (Inch)	ID: 5.225 ± 0.037 CS: 0.210 ± 0.005 OD: 5.645
Actual (Metric)	ID: 132.72 ± 0.94 CS: 5.33 ± 0.13 OD: 143.380

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.