Chartpak AD Markers, Tri-Nib, 25 Assorted Architectural Colors in Tabletop Cube are professional, xylene-based markers for art and design. The Tri-Nib permanent marker blends and transfers on paper, acrylic, ceramic, egg shell and more. The rich, vibrant colors are perfect for blending and shading, and won't streak or feather. Use with colorless blender [P-O, Sold separately] to create unique colors, transfer images and produce watercolor-like effects with colored pencil, graphite and charcoal. Non-toxic, conforms to ASTM D 4236. Made in USA.