The sketch artists must-have drawing tool must be a sharp, precise fine black pen. Therefore, we are pleased to introduce the SketchOne. It is available in a variety of line widths for the discerning sketcher making it optimal for outlines, shading, and all other types of markings. Black, permanent, non-fading ink, airplane-safe, erasable on transparent sheets, cap can be left off for up to 18hrs. without nib drying, metal-clad synthetic nib, non-refillable. Line widths: 0,1 mm, 0,3 mm, 0,5 mm, and 0,7 mm.