We use standard US sizing. Please use the table below to determine your size.

Diameter (mm) Circumference (mm) US UK
15.9 mm 49.95 mm 5
16.7 mm 52.46 mm 6
17.5 mm 54.98 mm 7
18.3 mm 57.49 mm 8
19.1 mm 60.00 mm 9
19.9 mm 62.52 mm 10
20.7 mm 65.03 mm 11