The first time I used a rapidograph pen, I was in love. The precise tip is a good match for what I want to produce via ink.
The first rapidographs I used were Koh-i-noor. They would clog and I would shake them. Then I saw Rotring brand rapidographs in a catalog. They were $35 per pen but I thought I would give one a try as they promised that they did not clog. The claim was true. They do not clog! I have been amazed by this fact after years of shaking and tapping. Even my .13 after weeks of not being used, still flowed. These are the only pens I now use.
