Size 7   :   85-90cm (suitable for 2-3 yrs old)  

Size 9   :   90-95cm (suitable for 3-4 yrs old)

Size 11   :   95-100cm (suitable for 4-5 yrs old) 

Size 13   :   100-110cm (suitable for 6-7 yrs old) 

Size 15   :   110-120cm (suitable for 7-8 yrs old)