Unique, xylene free permanent marker for wet surfaces | The unique ink formula in the Artline 47 allows for clear marking of wet non-Porous surfaces such as metal, plastic, Styrofoam, etc. Even if underwater | Permanent marker for most non porous wet surfaces | Ideal for use on surfaces such as metal plastic Styrofoam etc | Marking becomes permanent as soon as it is exposed to air | Ideal for fresh food markets, building trades, marine industries etc.