0116 275 4720 sales@m-seals.co.uk



M Seals’ products are quality assured and we keep over £1.5m of stock ready for next-day delivery. We respond to customers quickly and provide reliable delivery of quality o-rings and sealing products.

We stock o-rings in a wide range of materials, including Nitrile, Viton®, EPDM, Neoprene®, Kalrez®, Silicone & PTFE. See below for a comprehensive list of materials.

Ranges of o-rings include British Imperial (BS1806), British Metric (BS4518), European Metric (ISO/DIN 3601), including German (DIN 3771), Swedish (SMS 1586/1588) and French (NFT 47 501). American (SAE AS568A, MS 29 513) and Japanese Metric (JISB 2401).

Many of our o-rings are available with various approvals including Norsok M710, FDA, WRC, WRAS, UL, DVGW, KTW, BGVV, KIWA, USP, NSF/ANSI, EN549, EN681-1 and EN682.

All approvals can be provided with full certification.

See our Compliance Documents & Technical Data Sheets page for further information.

20,000 sq ft distribution centre

>£1m of sealing products kept in stock

Next day delivery for orders placed by 5pm


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M Seals has a goal to be recognised globally for quality, reliability and expertise in all aspects of our business. It is also our intent to provide the highest quality products to our customers while complying with customers’ contractual requirements, our company policies and procedures, and applicable safety, quality and environmental regulations.

M Seals Leicester is approved to BSI ISO9001-2015 and M Seals Newcastle is approved to BSI BS EN9120-2018.

See our compliance documents.



The following materials and advanced versions of them are available in a number of colours and shore hardness.

Nitrile O-Rings (Buna-N)

General purpose material, also known as ‘medium nitrile’ commonly used in applications sealing hydraulic fluids with a temperature range of -40°C to +120°C (depending on compound)

Viton® O-Rings (FPM, FKM)

An excellent resistant material used to seal a much wider range of oil and chemical media with a temperature range of -30°C to +200°C (depending on compound)

Neoprene® O-Rings (CR)

Also known as Chloroprene, another general purpose material similar to Nitrile in its mechanical properties used to seal refrigerants with a temperature range of -40°C to +120°C (depending on compound)

EPDM O-Rings

An excellent material for sealing water, steam, and glycol’s / brake fluids with a temperature range of -50°C to +150°C (depending on compound)

Silicone O-Rings (VMQ)

Silicone has the widest temperature range of -60°C to +200°C (depending on compound) only used for static sealing due to it’s low mechanical strength.

Kalrez® O-Rings

A Dupont material with the best chemical resistance similar to that of PTFE and a temperature range of -40°C to +326°C (depending on compound)

High Nitrile O-Rings

As per standard nitrile material but with a higher >45% ACN (Acrylonitrile) content for increased resistance to oils and solvents with a temperature range of -40°C to +120°C (depending on compound)

Aflas® O-Rings

A unique TFE/P material which is a copolymer of tetrafluoroethylene and propylene with a fluorine content of approx. 54% excellent for chemicals and steam applications with a temperature range of -20°C to +200°C (depending on compound)

Fluorosilicone O-Rings

Similar to Silicone with enhanced properties to temperature extremes and improved resistance to oils, acids and alkaline chemicals with a temperature range of -60°C to +200°C (depending on compound)

HNBR O-Rings

Hydrogenated nitrile is NBR treated with hydrogen enhancing it’s mechanical properties and increasing it’s temperature capabilities to -30°C to +150°C (depending on compound)

SBR O-Rings

Styrene butadiene rubber is a general purpose material used in a variety of mechanical applications like conveyor belts and car tires with a temperature range of -25°C to +100°C

Natural Rubber O-Rings

This essential raw material is used in the creation of all of our elastomeric materials specified.

Polyacrylate (ACM) O-Rings

Polyacrylic rubbers have good resistance to ozone compared to nitrile but poor resistance to moisture and water with a temperature resistance of -10°C to +150°.

Butyl O-Rings

A synthetic rubber mainly available as sheets and tapes, also used as an adhesive and solvent in tubes.

PTFE O-Rings

Polytetrafluoroethylene is a fluoropolymer with many applications it is the most chemically resistant material with an outstanding temperature range of -196°C to +260°C

Vamac® (AEM) O-Rings

A Dupont material similar properties to Polyacrylate (ACM) but with a lower temperature capability of -30°C.

Perfluoroelastomers (FFKM) O-Rings

Alternative to Kalrez with excellent chemical resistance and available from a variety of different sources.

XNBR – Carboxylated Nitrile O-Rings

A special nitrile material with enhanced mechanical strength with a temperature range of -25°C to +125°C.

FEP Encapsulated O-Rings

A seamless FEP encapsulation around a Viton or silicone elastomeric inner o-ring giving it excellent chemical resistance with a temperature range of -60°C to +200°C (depending on compound of inner O-Ring)

Many of the above are available with various approvals, including full certification Norsok M710, FDA, WRC, WRAS, UL, DVGW, KTW, BGVV, KIWA, USP, NSF/ANSI, EN549, EN681-1 & EN682.

Further Information


Download our British Standard O-Ring Size Guide


Download our O-Ring Catalogue