Uni-Ball Chalk marker - 5mm tip Buy chalk markers at Suitup Art Supplies. The Uni-Ball chalk marker set is ideal for festive window drawings and decorations. Uni's chalk markers consist of liquid chalk for use on memo boards, blackboards, glass, plexiglass, metal, whiteboards and other non-porous materials. Chalk marker can be wiped away with a wet cloth, but it is weatherproof after drying. Thus, the chalk marker is also suitable for outdoor use. Ideal for creating menus, cheerful decorations, billboards, notes and much more. Available in 5 colors.