O-rings

An O-ring is the most widely used sealing element you'll find in engineering — a simple ring with a circular cross-section that reliably seals a joint against liquids, gases and dust. It's precisely this simplicity that makes it so versatile: it serves as a static seal (between two fixed surfaces, for example under a cover or a flange) as well as a dynamic seal (on moving parts such as pistons and shafts). You'll come across it in hydraulics and pneumatics, in the automotive industry, in food processing, in chemistry, in water and steam systems and in the energy sector. If something flows or needs to be sealed, there's a good chance an O-ring is behind it.

In practice, O-rings are made from a handful of main materials: NBR (nitrile rubber) as the proven choice for oils and everyday environments, HNBR for higher demands on temperature and durability, FKM (also known as Viton®) for aggressive media and high temperatures, FFKM for the most demanding chemical environments, EPDM for water, steam and brake fluids, VMQ (silicone) for food processing and extreme temperature ranges, and finally PU (polyurethane) for high pressures and abrasion resistance. Our catalogue carries NBR, FKM, EPDM, silicone (VMQ) and PU; other compounds we can look into on request. We stock both dimensional systems — metric as well as the imperial AS568 — across a wide range of diameters, from the smallest right up to large sizes. In total that's over 6,000 items, many of which are in stock and ready for immediate dispatch.

Choosing the right O-ring essentially comes down to two parameters. The first is the size: the inner diameter d1 and the cross-section thickness d2, both in millimetres. It's this pair of numbers that uniquely determines which ring fits your groove — and here we recommend using the quick size search in the configurator, where you simply enter d1 and d2 and the system instantly shows you the available items. The second parameter is the material, which is chosen according to the medium (what the ring is meant to seal), the operating temperature and the pressure. If you're not sure which material to pick, use the "We'll advise you — 3 questions" guide on the site: answer a few questions about your application and we'll recommend a suitable compound. Together these two tools handle the entire selection without a phone call — first you find the size, then you confirm the material.

When it comes to dimensions, it pays to know a few standards. Both the metric system and the imperial AS568 have defined size series and tolerances set by standard, so the size you find with us matches what you have in your documentation or on the old part. Material hardness, given in degrees Shore A, also deserves attention. You'll commonly encounter two values: 70 ShA is a softer material that conforms better to the surface and therefore seals better at standard pressures, while 90 ShA is harder and is suited to situations where pressure is higher or where there's a risk of abrasion and the ring being extruded into a gap — polyurethane being a typical example. The choice of hardness is therefore not a minor detail; it directly affects the service life of the seal in a given application.

Why buy specifically from oringy.sk? First and foremost for availability — since we keep many sizes in stock, we process orders quickly and deliver to Slovakia as well as the Czech Republic without unnecessary waiting. The whole site is available in five languages, so a colleague or supplier across the border can find their way around it too. When you're stuck, technical support is on hand — Filip Meheš will help you with a specific application as well as with a non-standard request. For businesses we offer purchasing on invoice with payment terms, so ordering fits seamlessly into normal B2B processes without complications.

Beyond the goods themselves, we also have your documentation and decision-making in mind. For every size you can download a technical datasheet in PDF format with the key parameters of that O-ring, so you have something to file directly in your folder or submit for approval. If you need a price for a larger order or for internal purchase approval, you can request a non-binding quotation — with no commitment, simply as a basis for your decision. The aim is for you to be able to resolve your entire enquiry with us on your own: from finding the size, through choosing the material, to placing the order — and to turn to us only when you genuinely need advice.

You may know O-rings by their colloquial name — in Slovak people often say "oringy", and in English you'll see the variant spellings "oring", "o-ring" or "O ring". It's the very same sealing element, just an everyday term. Whether you search for "oring", "o-ring", "O-ring" or "sealing ring", you're in the right place; every one of those terms brings up the same thing here. And you don't always need just a single piece: for maintenance teams and workshops an O-ring kit often comes in handy — an assortment of several sizes together, so that when a repair comes up you can pick out the right one straight away. If you're interested in a specific kit composition or a larger quantity of a single size, get in touch and we'll put together a tailored offer.

When choosing, it's also worth knowing the relevant standards and certifications — though we stick strictly to the facts here. O-ring dimensions are defined by standards such as the metric series (ISO 3601) and the imperial AS568, which set out the diameter series and tolerances — which is why a size from our catalogue matches what you have in your documentation. For health or food-contact suitability, what matters is the specific compound, not the material as such: for silicone, for example, the standard FDA 21 CFR 177.2600 is cited, but whether a given ring actually meets it applies only to a certified compound. So when you have a requirement for a specific certificate, approval or a cross-reference to a standard, we'd rather check the available documentation for that particular item than quote numbers blindly — for a specific requirement, Filip will be glad to help.

The typical material choice also varies by industry. In hydraulics and pneumatics NBR leads the way, with polyurethane at higher pressures; in the automotive industry HNBR and FKM join them on account of temperature and fuels; in food processing and medicine silicone (VMQ) and EPDM dominate; in chemistry and the energy sector it's FKM, and for the most aggressive processes FFKM. Water, steam and brake systems belong to EPDM. If you're not sure which material suits your industry, the "We'll advise you — 3 questions" guide will suggest one based on the medium, temperature and pressure — and in borderline cases our technician will confirm it for you.

Put simply — O-rings are a small part with a big responsibility, and choosing the right one decides whether a joint seals or leaks. All it takes is two pieces of information, the size and the material, and you can confirm both with us in a few minutes thanks to the configurator and the guide. With over 6,000 line items in the range, five materials in the catalogue and plenty of stock on the shelf, there's a strong chance that what you're looking for — whether it's ordinary NBR, temperature-resistant FKM (Viton®), EPDM for water and steam, silicone for food processing or PU for high pressures — you'll find with us, ready to ship.