Inside Diameter
MM		 Inside Diameter
Inches		 Italy
Spain		 USA,
Canada,
Mexico		 UK Ireland,
Australia,
New Zealand,
South Africa		 Germany
France		 Japan,
China,
India,
South America
15 mm 0.59 6,5 4 H 46.8 7
15.3 mm 0.6 8 4.5 I 48 8
15.6 mm 0.62 9,5 5 J 49.3 9
16.2 mm 0.63 10,5 5.5 K 50.6 10
16.6 mm 0.65 12 6 L 51.9 11
16.9 mm 0.67 13,5 6.5 M 53.1 13
17.2 mm 0.68 14,5 7 N 54.4 14
17.8 mm 0.7 16 7.5 O 55.7 15
18.1 mm 0.71 17 8 P 57 16
18.5 mm 0.73 18,5 8.5 Q 58.3 17
19.1 mm 0.75 20 9 R 59.5 18
19.4 mm 0.76 21 9.5 S 60.8 19
19.7 mm 0.78 22,5 10 T 62.1 20
20.4 mm 0.79 23,5 10.5 U 63.4 22
20.7 mm 0.81 25 11 V 64.6 23
21.0 mm 0.83 26 11.5 W 65.9 24
21.6 mm 0.84 27,5 12 X 67.2 25
22.0 mm 0.86 29 12.5 Y 68.5 26
22.3 mm 0.87 30 13 Z 69.7 27
22.9 mm 0.89 32 13.5 Z+2 71 –
23.2 mm 0.91 33 14 Z+3 72.3 –
23.6 mm 0.92 34,5 14.5 Z+4 73.6 –
24.0 mm 0.94 35 15 Z+5 74.8 –