The two digit series in the 1960s replaced the three digit series, except for the 149 whose production was uninterrupted. These pens were designed by Alexandra Count Goertz, who also designed for BMW!
The mid-sized 34 is from the 1960s with an intarsia nib. It is similar in design to the 72 and the 1x and 2x series. I really like the size of this pen - it's not too fat or thin, not too long or short. Just right! My pen has a double broad stubbish nib that lays down a really wet line! This series is made of resin and the pens are piston fillers. One key difference between the 3x and the other series is that it is a screw cap instead of push cap.
The two digit series was numbered in a way where the first digit represents the tier of the pen i.e. 1 = top tier, 2 = mid-tier, and 3 = economic tier. The second digit in the model number represents the pen and nib size i.e. 2 = standard sized pen (in my opinion), and 4 = large or longer size. So, the 34 here is quite a nice long pen. You can notice how it is just a little longer and fatter than the 72 and 22 in this picture on the right (the 34 is the pen at the bottom of the lot).
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