The Staedtler 700 Technical Mars Matic Drafting Lettering Pen Set is an excellent choice for drawing with ink on drawing board and drawing paper. A channel inside the technical pen ensures optimum pressure equalisation. At the same time, a movable drop weight controls the steady flow of drawing ink onto the paper via a tube located at the tip of the pen. This results in a consistent line width, which is determined by the diameter of the tube.