Delivering Fluid Sealing Solutions Since 1972

Nitrile O Rings (NBR)

The UK’s largest selection of Nitrile O Rings (NBR)

M Barnwell Services’ range of Nitrile O Rings (NBR O Rings) offers good mechanical properties and resistance to mineral oil-based lubricants greases, and fuels. They are available in a wide variety of shore hardness and specialist compounds.

We have over 50 million O Rings and Back-Up Rings in stock servicing many industries. These include Water, Pump and Gas, Agriculture, Food and Drink, Rail, Automotive and Bus Truck and Trailer.

Nitrile O Rings

About Nitrile O Rings and its Features:

Nitrile elastomer (NBR), the comprehensive term for Acrylonitrile Butadiene Copolymer, stands out as a cost-effective and widely utilised material. Nitrile O Rings, typically available in standard black with a hardness ranging from 40 to 90 Shore A, have proven durability. They exhibit resilience in temperatures spanning from -40°C to +135°C (with intermittent/compound-specific capabilities reaching up to +150°C). Tailoring is possible for temperatures as low as -65°C and up to +120°C (for low-temperature applications).

These elastomers consist of varying ratios of the copolymer butadiene and acrylonitrile. Compounds with approximately 32% Nitrile (ACN) content, known as “Medium Nitrile,” enjoy significant popularity. On the other hand, compounds with around 50% Nitrile (ACN) content are termed “High Nitrile” and are particularly recommended for applications involving Hydrocarbon fuels. Conversely, compounds with roughly 18% Nitrile (ACN) content, labeled as “Low Nitrile,” find their niche in low-temperature applications.

Key Uses of Nitrile O Rings:

Marine, aircraft, and automotive fuel structure, off-road equipment, oil-resistant applications of all types, and low-temperature military uses. Furthermore, it can be compounded to Hygienic FDA applications. Nitrile combines superb resistance to petroleum-based oils and fuels, hydraulic fluids, water, alcohol, and silicone greases. It also presents a great balance of working properties such as a low compression set, high abrasion resistance, and high tensile strength.


Nitrile O Ring compounds are, however, confronted by a slight quantity of Ozone. A commonly used compound in Nitrile rubber is a phthalate-type plasticizer that can migrate out and generate issues with some plastics. In addition, new regulations on some phthalates have limited their use.

For further details about Nitrile (NBR) O Rings visit our Material Properties page.

If you would like more information about our range, download our catalogue, see Nitrile Comparison Chart, or contact a member of the team.

E & OE.


No limitation to dimensions with over 10,000 different sizes available from stock.


Nitrile (NBR), Buna-N

Temperature Range

Between -40°C and +135°C (intermittent/compound-specific up to +150°C)
Can be formulated for temperatures ranging between -65°C and +120°C (low-temperature)


Between 40 and 90 (Shore A)


O Ring Metric & Imperial Kits, Selection Boxes, Splicing Kits & Top-up Bags available.
Bespoke O Ring Kits and Selection Boxes also available.

Associated Products

Encapsulated ORings (FEP/PFA), Lube, Gauge / O Ring material tester, Quad Rings® (X-Rings), Nu-lip Rings, O Ring Cord, Tube, Anti-Extrusion Rings, Splicing Kits, Back-up Rings, Lubricants & Adhesives