Size 7   85-90 cm  (suitable for 2-3 yrs old)
Size 9   90-95 cm  (suitable for 3-4 yrs old)
Size 11 95-100 cm  (suitable for 4-5 yrs old)
Size 13 100-110 cm  (suitable for 6-7 yrs old)
Size 15 110-120 cm  (suitable for 7-8 yrs old)