Size Reference
SIZE 21=inner length 14cm
SIZE 22=inner length 14.5cm
SIZE 23=inner length 15cm
SIZE 24=inner length 15.5cm
SIZE 25=inner length 16cm

SIZE 26=inner length 16.5cm
SIZE 27=inner length 17.2cm
SIZE 28=inner length 17.8cm
SIZE 29=inner length 18.5cm
SIZE 30=inner length 19.8cm
SIZE 31=inner length 20.4cm
SIZE 32=inner length 19.5cm
SIZE 33=inner length 21.1cm
SIZE 34=inner length 21.7cm
SIZE 35=inner length 22.2cm
SIZE 36=inner length 22.7cm