Zig Posterman Broad Chisel This marker has a 1/4" wide chisel tip Makes a 6mm wide mark. High Opacity, Waterbased pigmented ink. Marks on most surfaces, including glass, metal, wood and plastic. Great for advertisements on glass. Marks stay on glass until you wash them off with glass cleaner. Also suitable for marking paper, plastic, mirrors, wood and stone. Great on posterboard. Safe - Non Toxic.