ITALIA UK  FRANCIA US CIRC. mm. DIAMETRO mm.
9 J 49 4.90 1.56
9.5 J-1/2 49.25 5 4.96 1.58
10 K 50 5.02 1.60
10.50 L 50.50 5.5 5.06 1.61
11 L-1/2 51 5.09 1.62
11.50 M 51.50 6 5.12 1.63
12 52 5.18 1.65
12.50 52.50 5.21 1.66
13 N 53 6.5 5.28 1.68
13.50 53.50 5.34 1.70
14 54 5.40 1.72
14.50 O 54.50 7 5.43 1.73
15 55 5.46 1.74
15.50 55.50 5.53 1.76
16 P 56 7.5 5.59 1.78
16.50 P-1/2 56.50 5.65 1.80
17 Q 57 8 5.68 1.81
17.50 57.50 5.75 1.83
18 58 5.81 1.85
18.50 58.50 8.5 5.84 1.86
19 R 59 5.90 1.88
19.50 R-1/2 59.75 9 5.97 1.90
20 S 60 6.03 1.92