AS568-251 Buna-N 90 Duro Black O-Ring for 5-1/8 ID X 1/8 CS

Buna-N O-Rings 90 Duro Black BN900100-251

$ 0.924 per Each

Minimum Order Quantity (MOQ): 33

Ships within 14 days

Qty	Price
33 - 37	$0.9240
38 - 81	$0.6930
82 - 162	$0.5544
163 - 324	$0.4158
325+	$0.3396

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Product Details

Material	Buna-N
Temperature Range	-40°F to 250°F
Cross Sectional Shape	Round
Hardness	90
Dash	251
Fractional	ID: 5-1/8 CS: 1/8 OD: 5-3/8
Actual (Inch)	ID: 5.109 ± 0.035 CS: 0.139 ± 0.004 OD: 5.387
Actual (Metric)	ID: 129.77 ± 0.89 CS: 3.53 ± 0.10 OD: 136.830

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.