High-quality, liquid chalk pens. Do not smudge (when dry) and do not fade. They are dirt-resistant and can withstand light rain. User-friendly: shake briefly, hold the tip depressed until the tip is coloured, write and leave to dry for a few minutes. Easy to remove with a damp cloth so that you can quickly start writing again. Writes on all non-porous surfaces such as chalkboards, glass, metal, plastic and much more. Harmless to health.