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® (FKM/FPM)Viton® A, Viton® B, Viton® GF, Viton® GLT, Viton® GFLT, Viton® ETPEthylene Propylene (EPDM)Silicone (VMQ), Polytetrafluoroethylene (PTFE) and Fluorosilicone (FVMQ). 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.

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

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

To view our RFQ Form – Click here.


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

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