Size Guide

SIZE INCH MM
XS 2.1-2.9 inch 50-70mm
S 2.7-3.5 inch 70-90mm
M 3.3-4.1 inch 85-105mm
L 3.9-4.7 inch 100-120mm
XL 4.3-5.1 inch 110-130mm
XXL 5.1-5.9 inch 130-150mm

Tips: If you are hesitating between two sizes, take one size up pls.