Technical pen

Staedtler technical pens
Staedtler technical pen divided in parts in comparison with 1 cent euro coin
Macro image of a 0.7 mm Rotring Rapidograph nib showing the flow control wire

A technical pen is a specialized instrument used by an engineer, architect, or drafter to make lines of constant width for architectural, engineering, or technical drawings. Technical pens may use either a refillable ink reservoir or a replaceable ink cartridge.

A technical pen built by Rotring.
A Rotring Technical Pen

Developed by StudentB