This water-based system is a combination of a liquid base and a colour additive. The Pre-Stain System is sprayed (using a spray gun) onto a vertical or horizontal concrete surface, either internally or externally. Pre-Stain is not like a paint which is a solid colour that totally covers visibility of the substrate. It can be applied as a single colour, yet more than one colour can be layered to customise a unique colour. The surface is then sealed with a gloss or matt sealer.