Delivering Fluid Sealing Solutions Since 1972

O Rings

O Rings – The UK’s largest collection from stock

M Barnwell Services are the largest independent manufacturer, stockist and distributor of O Rings and Back-Up Rings in the UK. With 50 million O Rings and Back-Up Rings in stock, we supply to over 5000 customers globally every month – quickly and reliably.

We have an extensive range of O Ring materials including Perfluoroelastomer (FFKM), Nitrile (NBR), Hydrogenated Nitrile (HNBR), Viton™ (or FKM/FPM)Viton™ A, Viton™ B, Viton™ GF, Viton™ GLT, Viton™ GFLT, Viton™ ETPEthylene Propylene (EPDM)Silicone (VMQ), Polytetrafluoroethylene (PTFE) Fluorosilicone (FVMQ) and Medical Grade. These can all be measured to imperial (BS1806, ISO 3601) and metric (BS4518) sizes, shore hardness and to a range of International, National and industry specifications, grades and approval standards.

We also offer a comprehensive range of quality FEP/PFA Encapsulated Rubber Seals and Hot Vulcanised Seals.

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For detailed technical information about our range click on the following links:

The high-quality range is competitively priced and if you are unsure on the material or size our expert team will help you select the right seal for your application.

If you would like more information about our range, download our catalogue, visit the Seal Maker Page or contact a member of the team.

If you are technical and understand your requirements please use our RFQ Form.


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


Nitrile (NBR), Viton® (FKM/FPM), Ethylene propylene (EPDM), EnDura™ (Steam Resistant), Silicone (VMQ), Fluorosilicone (FVMQ), ), Viton® A, Viton® B, Viton® GF, Viton® GLT, Viton® GFLT, Viton® ETP

Perfluoroelastomers (FFKM) including: Perlast™, Perlast Ice™, Simriz™, Gplast®, Kalrez®, Chemraz®, and others

Polyurethane (AU), Hydrogenated Nitrile (HNBR), Aflas® (FEPM), Polytetrafluoroethylene (PTFE), Neoprene (CR), Encapsulated (FEP/PFA) Styrene Butadiene (SBR), Anti Explosive Decompression Compounds (AED), Viton Extreme®, Metal Detectable, X-Ray Detectable, & many more.

O-Ring shore hardness - range from 40 Shore to 90 Shore.

O-Ring colours - A range of different colours available, which subject to minimum production quantities

O-Ring installation - Coating to aid lubrication can also be supplied


British Imperial (BS1806) and Metric (BS4518). European Metric (ISO 3601), including German (DIN 3771), Swedish (SMS 1586/1588) and French (NFT 47 501). American (SAE, AMS, AS568) and Japanese Metric (JISB 2401), SAE J515 and ISO8434-3 (SAE O ring boss hydraulic adaptors).


WRC, WRAS, FDA, DVGW, KTW, BGVV, KIWA, USP Class VI, NSF, ACS, EU2002/72, EN681-1, EN549, 3A Sanitary, NORSOK and EN682

Manufacturing Capabilities

Injection Moulded, Compression Moulded, Hot Vulcanised, Room Temperature Vulcanised (RTV), Butt / Scarf Joints, CNC Machined, Cleanroom Prepared


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

Bespoke O Ring Kits and selection Boxes are also available

Viton™ Information

Viton™ is a trademark of The Chemours Company FC, LLC. M Barnwell Services does not manufacture Viton™ products

Associated Products

Encapsulated O-Rings (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, Anti-extrusion Rings, Lubricants and Adhesives