There are two types of ruling pen, both used for fine lines and borders in indian ink, gouache, gold and drawing ink. The thickness of the line in both pens is finely adjusted by turning the metal screw wheel. Both pens have black plastic handles and are supplied in a plastic dust wallet.
The solid ruling pen has a 140mm handle.
The cross-hinged ruling pen has a 135mm handle. The hinge allows the pen's blades to be opened for cleaning without altering the line width setting.