Technical Pen Markers by Alvin Penstix Waterproof - Perfected to meet the artist's need for a black fiber tip pen with permanent, waterproof, fast-drying and fade proof ink. (Alcohol based, contains soluble dye stuffs but no solid pigments.) These new Penstix technical pen markers produce a clean, sharp line with no clogging or paper penetration and will not smear when dry. Plastic fiber nibs are encased in metal sleeves of the technical pen markers for durability and ease of use with straightedge drawing. The Alvin Pensticks are excellent for drawing, sketching, illustration, fine art, lettering, technical drawing, scrapbooks, cartooning or any form of graphics. Features pocket clip and ribbed cap which fits snuggly on barrel. Available in three line widths. Exceptionally long write out of over 3,000 ft. with consistent density and without fading, Alvin Penstix technical pen markers.