AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

O-Rings vs. Lip Rings

Machinery often holds pressurized liquids or gasses, and the mating surfaces between such components routinely feature an O-ring or lip ring. While both of these components seal mating surfaces to prevent leaks, they are slightly different from one another. Those interested in learning more about the differences between O-rings and lip rings are encouraged to read the following blog.

In order to understand their differences, it is important to know the structure and function of both O-rings and lip rings. To start, O-rings are elastomeric, mechanical seals that are circular in shape; typically made of an elastic material, these rings expand when exposed to heat and pressure, and when cooled, they return to their original size and shape. This means that they are built to withstand pressure while keeping the environment sealed inside a system free from leaks or contaminants. Although lip rings are also made from an elastomeric material with a ring-shaped design, they differ from O-rings in that they feature a groove around the inner perimeter.

Despite their similar shape, the inner groove or lip of a lip ring allows them to fit inside a notched mating surface, while O-rings feature a totally smooth interior and exterior. In general, these two ring types are employed in different sealing applications, as O-rings tend to be used in reciprocating seals, while lip rings tend to find use as rotating shaft seals.

Initially developed at the start of the 20th century, O-rings were fabricated as incredibly simple components which are still widely used to this day. Additionally, they have remained similar in form and function since their introduction. O-ring seals are part of a flexible range of O-ring kits, and they consist of a donut-shaped component. Their main function is to create a tight seal between two other components so that gasses and liquids are unable to escape, and they are often utilized in high-pressure environments in which a cork or regular gasket would likely fail. Moreover, they work by sitting inside a groove or channel between two different surfaces/components that will be mated. With pressure, the O-ring distorts inside the groove, improving its overall sealing force up to a certain pressure before it begins to fail. Overall, this is why it is important to obtain the correct balance between its material, size, and working environment. As such, O-rings are often used to seal joints between separate parts in applications including pumps, cylinders, connectors, and valves.

On the other hand, lip rings feature a flexible lip which can compensate for large tolerances and the presence of gaps between the sealing surfaces. This lip is meant to face the source of pressure which benefits the seal in two ways: first, the lip is energized by the pressure source to increase its sealing force of the mating hardware, and second, the resiliency of the material and its flexibility will compensate for the variations in their clearance gap. This makes them perfect to utilize in applications that require overcoming hardware tolerances and clearance gaps in axial applications.

Those searching for reliable bearings, fasteners, IT hardware, and aircraft parts can trust NSN Catalogue, where we are dedicated to providing our customers with quality services and products. With more than 2 billion new, used, obsolete, and hard-to-find components available for your immediate purchase, you can trust you will find what you are looking for on our online database. As we choose to source all of our products from leading global manufacturers to ensure their quality and reliability, we proudly operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation. Our expansive supply chain network spans the United States, Canada, and the United Kingdom, ensuring that we can expedite shipping times for both domestic and international customers alike. At your leisure, take advantage of our RFQ services to acquire a customized quote from one of our dedicated account managers. However, for further inquiries, call or email us with any questions, and we will be more than happy to assist you in the parts procurement process.


Semiconductor's Certifications and Memberships
The only independent
distributor with a
  • All Orders are fulfilled in the U.S.A.
  • All shipments must comply with U.S.A export laws.
  • No exceptions.
Intrepid Fallen Heroes Fund

“We Proudly Support Intrepid Fallen Heroes Fund that serves United States Military Personal experiencing the Invisible Wounds of War : Traumatic Brain Injury (TBI) and Post Traumatic Stress (PTS). Please visit website ( and help in their valiant effort”.

Thank You for Visiting.

We Hope that You Will Visit Us Again the Next Time You Need NSN Parts and Make Us Your Strategic Purchasing Partner.

Request for Quote

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.