It has a buckle. It is a perfect fit. 10 years old, chest 74cm. Dress length 87cm....... 11 years old, chest 76cm. Dress length 90cm....... 12 years old, chest size 78cm. Dress length 92cm.. 13 year old chest size 80cm. Dress length 94cm. Chest size for 14 year old. 82cm. Dress length 96cm.....