Design, Engineering and Technical Drawing is one area which was once done entirely with drawing pens, geometry tools, compasses and other technical drawing equipment. Nowadays a lot of it is done using Computer Aided Design (CAD) but there is stilla thriving community of engineers, architects, designers and hobbyists that rely on technical drawing tools, and good old fashioned paper to get the job done. Sometimes it is the only real way to get a feel for your project, and makes you think about each individual line.
Edding 141 Permanent Pen
Practical permanent marker pens designed to write on almost any non-porous surface, including glass and plastic,