This Uni Blue 520 Marker is suitable on most surface types making it a versatile option for your art room or workspace. The alcohol-based ink is xylene-free, smudge-proof and waterproof so you don't need to worry about causing smears in your work. • It has a medium bullet tip and will produce lines between 1.0 and 3.0 mm. • It's suitable for using on wood, metal, vinyl, glass, plastic and more. • The ink is designed to be permanent and long lasting.