I have a Soviet fountain pen along the same model as the Parker 21/51. I've had three 21s develop a crack in the same place as the cheap plastic becomes very br

I have a Soviet fountain pen along the same model as the Parker 21/51. I've had three 21s develop a crack in the same place as the cheap plastic becomes very brittle with age, but no such issue with its Soviet twin. The Soviet one also uses a more old-fashioned button filler mechanism that holds more ink than the Parker's aerometric bladder. I used it a lot for note-taking in school.