Are you trying to colour match your holds between brands?
Here are a few things to know:
RAL shades vary from one manufacturer to the next, even if the given RAL colour is the same.
(Tech note: This is due to the base PE / PU material having many varying shades, and this gives a slight taint to the RAL colourants.)
Flathold, Cheeta, Artline (PU), Kilter Europe will always match perfectly
Volx's Colours are given below: