These Edding Chalk Markers produce a more professional and elegant script or drawing - better than any chalk, and are used for non-permanent designing, decorating and writing on non-porous surfaces. The opaque, water-based liquid chalk has a neutral smell and can be wiped off virtually all non-porous surfaces with a damp cloth. Usage;. Shake the marker with the cap on. Remove the cap. Pump the marker with the nib downwards on e.g. a piece of scrap paper. This Classpack of chalk markers includes;. 30 assorted markers (Black, Red, Green, Neon Yellow, Neon Orange and White), with a round nib at a stroke width of 2-3mm,. 5 White markers with a chisel nib at a stroke width of 4-15mm.