About the size: Waist 75-90cm,we advice size S; Waist 85-100cm,we advice size M; Waist 95-110cm,we advice size L; Waist 105-125cm,we advice size XL; Back Support helps for following symptoms: Humpback Bad posture kyphoscoliosis Spinal curvature Thoracic kyphosis Thoracic lordosis Clavicle fracture Misaligned Spine Round shoulder The most practical gifts For parents:treatment the back pain and lumbar pain. For children:correct posture. Supporting design helps correct bad body posture of back and shoulder ,Posture Corrector Belt Pulls shoulder & back to correct posture. Posture Corrector Belt Provides gentle back support,Prevention of adolescent customary humpback Non restricting unisex design for men and women,Fully adjustable, comfortable & easy to wear For office persons,Supporting design helps correct poor posture Please kindly note : Items will be repackaged to save your shipping charge & to be environmentally friendly. We guaranty the item will be protected well in buble bags, No retail box! Note:Please allow 1-3cm error due to manual measurement. And due to the light and screen difference, the item's color may be slightly different from the pictures. Please kindly understand. Make sure you don't mind before you order. Package included: 1pcs Back Support