Grog BLACK MAGIC INK is a low viscosity alcohol-based invisible ink, with a satin finish, made for any felt tip pump-action marker such as the Cutter 08 BMI. Black Magic Ink 70 is highly staining with a stunning flow, for indoor and outdoor use, suitable for non-porous surfaces only. This product line is for writing without attracting attention: once applied, the invisible ink only reacts under UV lights until it turns into a deep dark brown colour. With BLACK MAGIC INK reality will become a mere, pocket-sized illusion.