The Difference between FPM, FKM and Viton®The terms FPM, FKM and Viton® very often cause confusion and lead to incorrect interpretations. All of these designations actually stand for one single base material:fluoro rubber. FPM is the international abbreviation according to DIN/ISO, whereas FKM nis the short form for the fluoroelastomer category according to the American standard ASTM. Viton® is the registered trade mark of DuPont Performance Elastomers. Zrunek uses the designation FPM for all of its fluoro-elastomer materials.。