Professional, concentrated, gel colours for colouring icing, marzipan, buttercream & more. ProGel® by Rainbow Dust Colours is a ready-to-use, professional grade, concentrated food colour. The smallest amount of gel can be mixed with sugarpaste, icing, buttercream, marzipan etc, to achieve your desired shade of colour. Presented in a compact, easy to use tube that allows clean handling and storage of the coloured gel.