The remarks concerning the subsequent use of incomplete series of numbers refer to the years after 1971. From the calibre indication one can deduce the diameter or hight of the movement, bearing in mind that three measures are used: the ligne, the millimetre and the douzieme.
a) The movement with the indication 12''' -400 has a diameter of 12 lignes = 27 mm (1''' = 1/12 French inch = 2,256 mm).
b) The movement with the indication 27-400 has a diameter of 27 mm.
c) A movement with a thickness of 20/12 is 3,76 mm high (1/12 = 0,188 mm). More ›