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 onRemove the capPump the marker with the nib downwards on e.g. a piece of scrap paperThis 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.