Chartpak Wood Frame Touch-Up Marker, Tri-Nib, Blender (Colorless), 1 Each (FTM-O) Colorless blender enables the creation of unique colors when used with several different Chartpak Frame Touch-Up Markers AD Marker's legendary tri-nib design offers fine, medium and broad widths Non-toxic, conforms to ASTM D 4236 Easy to use Made in USA