Size 3（7.1 inch）is suitable for kids under 8 years old Size 4（7.5 inch）is suitable for youth under 15 years old Size 5 （8.7 inch）is suitable for all people all ages Recommended air pressure is around 0.8 bar which means after inflation，the ball bounce back 60%-80% Enjoy the sports，feel the spirits coming from legends. Attention：May be Wrinkles on Surface,No impact on usage.The ball requires inflating air from time to time because it has natural leakage,we recommend to inflate the ball before kicking. SAFE DESIGN Thicker PU Surface,Soft Material,Anti explosion design Tight weaved,Make sure the stability of structure Rubber bladder The Soccer ball can be applied outdoor or indoor，as all people know，all material can be wore out，so the life of soccer ball depends how much time you use and how you use it，There is possibility that 1/1000 couldn't be inflated.Please exchange. #productDescription h3 { margin: 0.75em 0px 0.375em -1px; }