Sizing

 US / CA
UK / AU
DIAMETER (MM)
DIAMETER (IN)
6

L

 16.51 0.64
7

O

 17.35 0.68
8

Q

 18.19 0.71
9 S 18.89 0.74
10 T 19.84 0.77
11 V 20.68 0.81
12 Y 21.49 0.84