Before buying, please check our size. We will have a size chart for each shoe. Please measure your foot size and find the size (Length of shoe/ cm) that suits you for purchase. After receiving the package, please ignore the size marked on the package. The size of the shoes is the size you purchased. If you are not sure, please contact us in time. Product specifications: Sole Material: Rubber Category: Roller Upper material: super fiber leather Wheel type: double row Wheel material: PU Category: skates feature: 1. Adjustable wheel: retractable rear wheel for skates and regular sneakers. 2. Type: Auto button. The security foundation of the invisible button. There is a button at the back of the shoe, hold it down, open the wheel, hold the button, then push the roller to the sole and release 4. Be careful when starting to slip For safety reasons, children must be accompanied by an adult when wearing these shoes. For professional users, they must weigh less than 90 kg. For beginners, they must weigh less than 100 kg. The grinding wheel is a fragile product that can be replaced. The life of the grinding wheel depends on where it is used and how it is used.