edding 4090 Chalk Marker, 4-15mm Chisel, Neon PinkHigh quality writing on blackboards and glass edding 4090 chalk marker Chalk marker for non permanent extra broad designing, decorating and writing on non porous surfaces, e. g. windows, dark boards, glass and mirrors. The chisel nib has a stroke width of 4 15 mm. The opaque, water based liquid chalk with a neutral smell can be wiped off virtually all non porous surfaces with a damp cloth. Opaque liquid chalk in a marker format. Extra broad stroke.