Halogen-free materials – such as Kaiflex HF – are more sensitive and less mechanically robust than  standard FEF, as they are lacking the stabilizing effect of halogen containing ingredients.
Materiali brez halogena – kot je Kaiflex HF – so bolj občutljivi in manj mehansko robustni kot standardni materiali FEF, saj jim manjka stabilizacijski učinek sestavin, ki vsebujejo halogen.