| Property | FKM (Viton®) | FFKM |
|---|---|---|
| Fluorine content | ~66–70% | >70% |
| Temperature range | –20°C to ~200–230°C | –20°C to ~327°C |
| Chemical resistance | Good; limited with strong acids, ketones, steam | Near-universal |
| Cost | Moderate | 10–20× higher |
Choose FFKM for extreme chemicals, purity requirements or temperatures above 250°C. See FFKM O-rings & Seals.