Size Guide example

Inner Diameter (mm) US Size UK EU Size Spain
13 0 A 41 1
13.3 0 B 42 2
13.6 0.5 C 43 3
14 1 D 44 4
14.3 1.5 E 45 5
14.6 2 F 46 6
14.9 2.5 G 47 7
15.2 3 H 48 8
15.5 3.5 I 49 9
15.9 4 J 50 10
16.2 4.5 K 51 11
16.5 5 L 52 12
16.8 5.5 M 53 13
17.1 6 N 54 14
17.4 6.5 O 55 15
17.8 7 P 56 16
18 7.5 Q 57 17
18.4 8 R 58 18
18.7 8.5 S 59 19
19 9 T 60 20