Compression set resistance defines long-term sealing performance, and FFKM excels with values typically below 15% after 70 hours at 300°C. This means FFKM O-rings maintain their sealing force for decades in static applications, whereas standard FKM might lose 50% of sealing force under identical conditions, leading to catastrophic leaks in critical process equipment. https://globalsealstech.com/ffkm-seals/