Size chart

Internal diameter (mm) Internal diameter (in) Desired size
15.3 mm 0.60 in 8*
15.9 mm 0.63 in 10
16.5 mm 0.65 in 12
17.1 mm 0.67 in 14
17.8 mm 0.70 in 16
18.4 mm 0.73 in 18*