1 Each. All-purpose marker pens feature tough plastic tips and a special ink formulation that lets them write on almost any surface. Tested on over 1,000 surfaces including glass, plastics, photos, ceramics, foil and metal. Ink is reliable under extreme conditions from the heat of a greenhouse to the cold of a freezer. Alcohol-based, odorless, waterproof, noncorrosive, xylene-free and toluene-free ink dries quickly, is light-resistant and frost-resistant, and safe for use on CDs and DVDs. Marker pens have ventilated caps and a long cap-off time without dry-out. Include an ergonomic grip zone for a perfect hold.