There are 2 Staedtler Mars mastic 700 technical pens. One was marked .35 & 0, and second .50 & 2.

There one pen marked RAPIDOGRAPH SL U.S.A.

And there is one more pen made in Germany by KOHINOOR RAPIDOGRAPH #0.

The pens feature a hard chrome-plated drafting tube and a double sealing system in the cap to prevent the ink from drying up.