DARICE-Victoria Lynn: Black Window Chalk Pen. This water-based liquid chalk pen is specially designed to write on glass surfaces. Have fun decorating car windows; mirrors; store fronts or other such surfaces-- it is dry-erase making clean-up easy. The tip on the pen is 1/2 inch and straight-- a feature exclusive to the Victoria Lynn line. This package contains one Window Chalk marker. Color: Black. Conforms to ASTM D4236. Imported.