Inside Diameter Inside Circumference US & Canada  UK & Aus
15.6 mm 49.3 mm 5
16.5 mm 51.9 mm 6
17.3 mm 54.5 mm 7
18.2 mm 57 mm 8
18.9 mm 59.5 mm 9
19.8 mm 62.1 mm 10 T
20.7 mm 64.6 mm 11 V