Rotring is an art supplier that has been in business since 1928. Their product line is highly specialised and limited to serving the needs of 2D artists, such as pencilers, sketchers, inkers and architectural designers. The rotring ArtPen is a shapely ink pen which uses cartridges, but may be converted for use with traditional fountain inks. The pen may be purchased on its own or as part of a multipiece calligraphy set. Additional pen tips -- nibs -- range in width from extra fine to approximately 0.09 inches, or 2.3mm. The pen is suitable for writing and calligraphy.
Dismantle the pen. Hold the grip and rotate the base of the pen, below the red line, counterclockwise to separate the nib and expose the cartridge well. Set aside the base of the pen (i.e., the part shaped like a paintbrush).
Pull the cartridge out of the nib.
Choose a nib. Identify nib width by examining the tip or reading the number on the top of the labelled cap.
Insert the cartridge into the nib, tapered end first.
Replace the base of the pen and rotate clockwise to screw into place.