Rubber O‑Rings – Everything You Should Know

What are O‑rings and What are They Used For?

Rubber O‑rings are circular seals with elastic properties, used to prevent fluid leaks. They come in various sizes and are suitable for both static and dynamic applications.

Types of O‑rings by Material

NBR O‑Rings

Operating temp: –30 °C to +90 °C. Resistant to oils, greases, hydraulic fluids (HFA, HFC), aliphatic hydrocarbons, and diluted acids/bases.

FKM/FPM (Viton®) O‑Rings

–20 °C to +210 °C. Excellent resistance to aromatic hydrocarbons, mineral/silicone oils, ozone, UV, methanol-blended fuels, making them standard for high-performance sealing.

EPDM O‑Rings

–40 °C to +150 °C. Ideal for HVAC, heating and wet environments: resistant to alcohols, organic/inorganic acids, ozone, UV, steam, and glycol-based brake fluids.

Silicone O‑Rings (VMQ/MVQ)

–50 °C to +240 °C (up to 300 °C versions). FDA‑approved, hydrophobic, electrically insulating, ozone- and heat-resistant.

HNBR O‑Rings

–30 °C to +150 °C. High wear and ozone resistance for oily and abrasive settings.

FEP/PFA O‑Rings

–60 °C to +260 °C. PTFE‑coated for superior chemical and mechanical robustness in extreme or offshore environments.

FFKM (Kalrez®) O‑Rings

–15 °C to +316 °C. Perfluorinated elastomer, unmatched chemical and heat resistance—used in aerospace, chemical processing, and food-grade high-tech applications.

Choosing the Right O‑Ring Material

Match O‑ring material to your operating temperature, fluid type, pressure, and sealing requirements. Check our comprehensive guide for proper sizing and material selection.