Skip to content
| Circumference |
Inside Diameter |
NZ, Australia & UK |
USA & Canada |
China, Japan & Singapore |
| 53.8mm |
17.1mm |
N |
6 3/4 |
13 1/2 |
| 55.1mm |
17.5mm |
O |
7 1/4 |
14 1/2 |
| 56.3mm |
17.9mm |
P |
7 3/4 |
15 1/2 |
| 57.6mm |
18.3mm |
Q |
8 1/4 |
16 1/2 |
| 58.9mm |
18.8mm |
R |
8 3/4 |
17 1/2 |
| 60.2mm |
19.2mm |
S |
9 1/4 |
18 1/2 |
| 61.4mm |
19.6mm |
T |
9 3/4 |
19 1/2 |
| 62.7mm |
20.0mm |
U |
10 1/4 |
21 |
| 64.0mm |
20.4mm |
V |
10 3/4 |
22 1/2 |
| 65.3mm |
20.8mm |
W |
11 1/4 |
23 1/2 |
| 66.6mm |
21.2mm |
X |
11 3/4 |
24 1/2 |
| 67.8mm |
21.6mm |
Y |
12 1/4 |
25 1/2 |
| 68.5mm |
21.8mm |
Z |
12 1/2 |
26 |
| 70.4mm |
22.4mm |
Z+1 |
13 1/4 |
27 1/2 |
