uni Chalk Markers are non permenant markers for use on non porous surfaces such as glass, plastic, and of course chalkboards. They are odourless, solvent and alcohol free and produce vivid, opaque and a vibrant colour finish. Simply write on and wipe off. uni Chalk Markers are also rain resistant which make them ideal for sign writing, for use in restaurants and cafes. This PWE-5M marker set includes; White, Yellow, Blue & Red. A bullet tip which produces a 1.8mm to 2.5mm line.