My dad's old Argoflex when I was about 11. Didn't get to use anything with a meter until I was 15. Until then it was walking around with the little paper insert. Made things a bit tricky with the Argoflex, which had a different f/stop progression (4.5, 6.3, 9, 12.7, 18) and shutter speed choices (10, 25, 50, 100, 200), than the Kodacolor or Verichrome Pan inserts. Did ok, though.