15mm Liquid chalk markers wet wipe products comes off with a quick wipe from a damp cloth yet they are waterproof and permanent under even the heaviest rainfall. This makes the wet wipe formula ideal for situations where the finished work might come into contact with dampness or water such as outdoor signage or work on an inside surface that might attract condensation such as an exterior window. Ideal Uses: Exterior signage, Scenic and commercial design, Any work in damp areas, Any internal work where the dry wipe characteristic is not desirable such as areas which may come into contact with clothing. Ideal Surfaces: Use on any non-porous surface including black and white boards, glass, metal, ceramic tile and others.