What Are Micro or Miniature O-Rings?

micro or miniature o-rings

In the most basic terms, o-rings work by sitting in a groove or channel between two components to create a leak-proof seal to prevent the unwanted escape of gases or liquids as the components are pushed together during the course of an application. As technology has advanced and smaller and smaller devices and mechanical elements have been developed, the need for micro or miniature o-rings has followed suit.

Generally, micro or miniature o-rings are defined as o-rings that measure no more than 1 mm (or 0.039 of an inch) in EITHER inside diameter (ID) or cross-section (CS). The cross-section is the width, or thickness, of the band of the torus-shaped seal. The inside diameter is the distance between one inside edge of the o-ring to the opposite inside edge. The third critical size measurement for o-rings is the outside diameter or the distance from one side of the outer edge to the opposite outside edge.

When talking about micro or miniature o-rings, it’s important to remember the classification can apply to either the CS or ID measurements. This means this class of o-rings could have an ID larger than the 1 mm maximum but still have a minuscule thickness measurement for the CS. And vice-versa.

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Small Size, Large List of Applications

Demand for micro or miniature o-rings, also sometimes references as tiny or small o-rings, is expected to increase as technological advances continue to make pursuing miniaturization efforts in various fields, industries, and applications possible. As machinery and devices continue to shrink to serve specific purposes, there will be a need for sealing solutions to follow suit.

When people think about technology and miniaturization, most will envision the wide assortment of electrical devices that have become more compact and more efficient in the modern age. A casual glance at the history of televisions or personal computers will illustrate this point effectively. But the avenues those advances have opened up apply to a host of fields.

For example, modern miniaturization has been impactful on the medical industry. From implantable defibrillators, pacemakers, and continuous glucose monitors to emergency response safety monitors and wearable health devices, medical devices can be used and placed in many more forms than ever before. Micro o-rings play a part in making these things possible and will also serve other equipment needs like syringes or microscopic equipment.

Another vector in which miniaturization has continued developing and consistently finding new uses is military or security applications. Surveillance technology, communications, and the advent of drone development in the last decade have all benefited from the ability to become smaller. From drones to earpieces, these devices and applications will need sealing solutions that can be engineered to fit in increasingly smaller and more demanding circumstances.

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Key Aspects to Consider for Micro or Miniature O-Rings

When looking to acquire micro o-rings for miniature-sized applications, there are three essential factors to consider — size, material composition, and availability.


This is the most significant determining factor for how well a micro o-ring will perform in an application and is the defining characteristic of this particular class of o-rings in general. Due to the minuscule and exacting nature of the measurements used — often under 1 mm or 0.039 (less than a tenth) inch — matching the correct parameters of your application with appropriately, and not approximately, sized micro o-ring is the most crucial consideration.

We are capable of providing micro or miniature o-rings as small as 0.36mm (0.014 of an inch) in cross section, or as small as 0.5mm (0.019 of an inch) in interior diameter.


The elastomer — the material or compound — used in your micro o-rings also carries great importance.

The type of substance employed will be influenced heavily by the kind of application the seals will be used in. Suppose you’re sealing an application used in the medical industry, for instance. In that case, you may require medical grade materials that are composed of USP Class VI approved materials or need to have Clean Room Manufacturing and Packaging directives.

There are preferred materials for chemical resistance applications and for working in food-related tasks. Consulting with expert engineers about the specifics of your application will help you identify the suitable material for your sealing solution.


The last facet to consider is whether you can find a distributor for the size of micro or miniature o-rings needed in the desired material. After recent production decisions by overseas providers, acquiring micro o-rings has become more difficult than in the past.

However, Marco Rubber & Plastics has the world’s most extensive o-ring inventory and production network at its disposal.

This means we can still provide timely delivery of every assortment of specialty sealing products or materials — including micro o-rings.

Why Marco Rubber is the Right Choice for Your Sealing Needs

With millions of products in stock and ready to ship throughout our production network, we can get the right seal quickly with our rapid order fulfillment capabilities. In many cases, your order will ship the same day it’s received. If custom formulation is needed, which may be the case with micro o-ring considerations, our responsive team will return your request often in a matter of hours with pricing and next steps.

No other o-ring provider will have more, or better, access to the myriad of custom-designed products available, including both micro and giant o-rings. Our team of engineers — with testing and material experts — will help you develop a specialty formulation of product type, size, and material that will provide the ideal solution to seal your success.

Additional Resources:

If you’re looking to purchase micro o-rings and need further help, these are for you:

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