Inside Diameter | US/AUS | UK | Germany | Spain | France | Italy | Japan |
16.6mm | 6 | L | 52 (16.6) | 12 | 52 | 11 | 11 |
16.9mm | 6.5 | M | 53 (16.9) | 13.5 | 53 | 12.5 | 13 |
17.2mm | 7 | N | 54 (17.2) | 14.5 | 54.5 | 14 | 14 |
17.8mm | 7.5 | O | 56 (17.8) | 16 | 55.5 | 15 | 15 |
18.1mm | 8 | P | 57 (18.1) | 17 | 57 | 16 | 16 |
18.5mm | 8.5 | Q | 58 (18.5) | 18.5 | 58 | 17.5 | 17 |
19.1mm | 9 | R | 60 (19.1) | 20 | 59.5 | 19 | 18 |
19.4mm | 9.5 | S | 61 (19.4) | 21 | 61 | 20 | 19 |
19.7mm | 10 | T | 62 (19.7) | 22.5 | 62 | 21.5 | 20 |
20.4mm | 10.5 | U | 64 (20.4) | 23.5 | 63.5 | 23 | 22 |
20.7mm | 11 | V | 65 (20.7) | 25 | 64.5 | 24 | 23 |