Spectra AD™ Markers are the latest edition the the AD® Marker family. An alcohol-based twin tip marker features brilliant color with less odor than the traditional AD® Marker. Painstakingly developed over several years, Spectra AD™ Markers were designed tip to tip, inside and out, with the artist in mind. Each air-tight cap closely matches the marker's ink, the barrel is ergonomically shaped and prevents rolling, ink capacity allows for maximum draw out, and the twin nibs offer the artist a wide range of line options in one marker. 12-marker set in Cool Gray Shades.