Faber Castell PITT artist pens are artist-grade markers made with extremely lightfast india ink. They are waterproof, odorless, and pH-neutral. Truly one of the highest quality pens available. This set is great for mixed/wet media, technical drawing, journaling, field sketching, or any fine art project. Comes with four distinct nibs: XS (0.1mm), S (0.3mm), F (0.5mm), M (0.7mm).