31654Z Point Size: 4mm, Line Width: 0.18mm Features: -Technical pen.-13 Different stainless steel nib sizes.-Refillable and most are sold individually or in sets.-Offer repair service to users.-Stainless steel drawing points in dual-designated line widths refillable.-Ink cartridge can be used on drafting film vellum or tracing paper.-Point size and ranging from very fine to very broad.-Loose sketching style or a finely detailed pointillist technique.-Moving in all directions without snagging or digging into the drawing surface.-Made in the USA. Collection: -Rapidograph collection.