Chartpak AD Marker Tri-Nib has three distinct line weights in one nib The markers deliver sparkling and brilliant color in fine point, medium weight or broad strokes ? with just a twist of the wrist. The unique shape of the Tri-Nib gives you precise control over your stroke, and the wide palette of permanent colors, which includes a complete range of pastels and grays, opens new worlds of creative possibility. The Tri-Nib Colorless Blender produces graduation/color from deep tones to light. Black and Super Black are also available in a Fine Point nib.From crisply articulated tight comps to broadly expressive illustrations, all the line you need is right at your fingertips Chartpak AD Markers are xylene based.