G-max Junior Jumping Shoes Boots for Kids, to 110lb(size Flexible,just on Your Weight) Exercise For 10 minutes Exercise A shock-Absorbing Device(Ball and Flexible Spring),Powered by patented ProzarxT&Ball technology to relieve the shock Reflector System On Back Side For using night Easy to use! G-Max Jumps Is One-Size-Fits-All. They can be tighten down to your Shoes&Foot size by adjusting the Shoes Belt(Strap) and Screw of on the side of Jumps. Flexible on your shoes size! Your foot size With your shoes on! You can see video) https://www.youtube.com/watch?v=n9nQbpOM7V8