Size Chart.

AgeSizeCircumference cmCircumference inches
4 – 9 Months4443-4817-19
9 M – 2 Yrs5048-5219-20.5
2 – 4 Yrs5252-5420.5-21.3
4 – 9 Yrs5454-5621.3-22
9 Yrs - 5856-6022-23.6