Bistro chalk markers create a dustless smooth layer and rich colors that are water based, non-toxic, and fade resistant. Perfect for home, office and school. Wipes away easily with a damp cloth. Try them on whiteboards, glass, backlit boards, presentation boards, metal boards and other non-porous surfaces. The color will remain until you decide to wipe it. This 3.625x6.875x.75 inch package contains four 6mm chalk markers in purple, white, pink and orange. Conforms to ASTM D4236. Imported.