17 x 5 mm is the tip size. Water-based opaque marker with a broad tip that is fade-proof, light-fast, and waterproof. Water-Based Pigment Ink: Eliminates Distasteful Odors Fantastic for Carton, Wood, Plastic, Canvas, Metal, and Other Smooth Surfaces for Arts & Crafts, Posters, Graffiti, and Graphic Art Works