I am a professional when it comes to the technical drawing. I can go through my hands work and 13 years of school experience for so many set square in 25 years, but belonging of Rumold in the league of the set square. Even this. Precisely machined and with a stable clip-on handle.
Of course, such precision instruments must also treat duly and maintain. So, always keep in the protective case, clean regularly and never let fall. Then decades some of it partially.
