AS568-338 Buna-N 90 Duro Black O-Ring for 3-1/8 ID X 3/16 CS

Buna-N O-Rings 90 Duro Black BN900100-338

$ 0.8968 per Each

Minimum Order Quantity (MOQ): 34

Ships within 14 days

Qty	Price
34 - 39	$0.8968
40 - 83	$0.6726
84 - 167	$0.5381
168 - 334	$0.4036
335 - 669	$0.3139
670+	$0.2915

Ordering in large quantities? Ask for a lead time quote — we'll get back to you with pricing and lead time.

Product Details

Material	Buna-N
Temperature Range	-40°F to 250°F
Cross Sectional Shape	Round
Hardness	90
Dash	338
Fractional	ID: 3-1/8 CS: 3/16 OD: 3-1/2
Actual (Inch)	ID: 3.100 ± 0.024 CS: 0.210 ± 0.005 OD: 3.520
Actual (Metric)	ID: 78.74 ± 0.61 CS: 5.33 ± 0.13 OD: 89.400

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.