Elastomer o-rings are manufactured in a variety of sizes and materials to withstand specific temperatures, abrasions, pressures, and more. They’re primarily used for sealing applications. At APM Hexseal, we have a long history of developing and manufacturing innovative sealing solutions, and we continue to serve more than 200,000 customers around the world.

What Are O-Rings?

Elastomer rings are donut-shaped mechanical gaskets used for sealing in both static and dynamic applications. O-rings offer several advantages:

  • Reduce friction to prolong the life of components
  • Seal against liquids, gases, dirt, and other potential contaminants
  • Resist extreme temperatures, abrasion, chemicals, pressure, grease, oil, and more

They can be made of many different types of polymers, including EPDM, chloroprene, nitrile, and silicone, which offer different levels of tensile strength, elasticity, temperature and chemical resistance, and more. O-rings are cost-effective to manufacture. They’re also easy to install and extremely reliable, making them a common choice in military, automotive, agricultural, marine, lighting, medical, electronics, and aerospace applications.

Types of Elastomer O-Rings

Your o-ring material depends upon your budget and the demands of the application. There are many materials to choose from:

  • Acrylonitrile Butadiene Rubber: Nitrile, or NBR, offers mineral oil resistance and practical temperature resistance, making it the most popular sealing elastomer for general purposes. For better oil and abrasion resistance, choose a grade with a higher content of acrylonitrile; for improved resilience and low-temperature flexibility, choose a low acrylonitrile grade.
  • Neoprene: Common in air conditioning and refrigeration applications, neoprene seals are self-extinguishing and offer good resistance to petroleum and oxygen. However, it will degrade with exposure to acetone, hydrogen peroxide, and hydrochloric acid, making it unsuitable for applications in which they are present.
  • Ethylene Propylene Diene Monomer: EPDM is an ethylene/propylene synthetic with exceptional heat, water, and weather resistance, making it a common choice for o-rings used in steam and brake fluid applications, as long as they don’t come into contact with grease or mineral oils.
  • Silicone: Non-toxic and easy to clean, silicone o-rings are FDA-approved for use in food and beverage production. Silicone o-rings resist corrosion, chemicals, solvents, and UV light. With the addition of a Teflon sleeve, they’re better able to resist wear and tear.
  • Viton: Developed by DuPont to withstand especially challenging environments, Viton comes in various grades that feature different temperature ranges, weather and chemical resistance, and more. They’re especially long-lasting, which can help you save money over time despite a higher up-front cost for this special material.


The elastomers listed above each have their advantages in specific applications:

  • General Purpose Sealing: Nitriles resist oil and hydrocarbon solvents while offering low gas permeability.
  • Aerospace and Automotive: Viton and silicone both have high-temperature resistance ideal for aerospace and automotive applications.
  • Brake Fluid Applications: EPDM provides excellent resistance to heat, steam, and water.
  • Refrigeration: Neoprene provides excellent strength and resistance to wear and tear.

Material Considerations

When choosing your o-ring material, you’ll need to consider the following:

  • Temperature resistance: High-heat applications will require a material like Viton, while silicone is a better choice for low-temperature applications ranging down to -175° F.
  • Chemical resistance: Consider the elastomer’s exposure to grease, oil, solvents, acids, esters, and more.
  • Hardness: Hardness is measured in durometers. Viton has one of the highest hardness ratings of 50-95.
  • Tensile strength: This is the amount of force that can be applied to an elastomer before it breaks. The more dynamic the application, the more tensile strength you’ll need your o-ring to exhibit. Silicone, for example, has low tensile strength.
  • Cost: Some materials are more expensive than others, but in some applications they may last longer, reducing your need for costly maintenance and repairs. Your budget considerations go far beyond the upfront cost of the material and into the long-term effects of making that choice.

APM Hexseal proudly produces elastomer o-rings for the U.S. military, the boating industry, medical equipment, communications equipment, and a wide range of other commercial and industrial applications. With more than 100 patents to our name, we’re dedicated to the innovation required to meet the ever-changing needs of our customers. Contact us to learn more about elastomer rings and our sealing solutions, or request a quote for your o-ring project today.

Standard Elastomer Options and Typical Properties for APM Hexseal® O-Rings

Letter & Code
Material Name Relevant
Temperature in °F
Temperature in °C
Tensile PSI Elongation % Abrasion
Compression Set
Silicone A-A-59588, Class 2,
GR60 or GR70
-80° to +425° -62° to +219° 500-1800 100-800 Recommended Recommended
FluoroSilicone MIL-DTL-25988C, Type 1,
Class 1, GR60 or GR70
-85° to +392° -65° to +200° 600-1400 100-700 Fair Recommended
Viton® A † ASTM D2000
75 Durometer
-13° to +482° -25° to +250° 2000-2200 300-400 Sufficient Fair
Buna N
ASTM D2000
70 Durometer
-167° to +248° -55° to +120° 1500-3000 400-600 Recommended Fair
Neoprene ASTM D2000
70 Durometer
-61° to +257° -52° to +125° 1500-4000 100-700 Fair Sufficient
(Ethylene Propylene)
ASTM D2000
70 Durometer
-76° to +302° -60° to +150° 1400-1600 500-600 Fair Recommended

† Viton® is a registered trademark of DuPont Performance Elastomers.

All content above is subject to change. Please contact us for up-to-date information.