EUR SIZE 21 = INSIDE 13CM

 EUR SIZE 22 = INSIDE 13.5CM

 EUR SIZE 23 = INSIDE 14CM

 EUR SIZE 24 = INSIDE 14.5CM

 EUR SIZE 25 = INSIDE 15CM

 EUR SIZE 26 = INSIDE 15.5CM

 EUR SIZE 27 = INSIDE 16.2CM

 EUR SIZE 28 = INSIDE 16.8CM

 INSIDE 17.3CM

EUR SIZE 30 = INSIDE 18.2CM