Sole material: Rubber Category: roller skate Upper material: super fiber skin Wheel type: double row Wheel material: PU Size: 3.5，4，4.5，5，5.5，6，6.5，7，7.5，8，8.5，9 （Please refer to size table for purchase，Thank you！！！） Category: roller skates For professional users, they need to weigh less than 90 kg. Beginners must weigh less than 100 kg. The wheel is a vulnerable product and can be replaced. The service life of the wheel depends on the place of use and usage habits. Please do not claim a refund for the quality of the wheel. The product itself has wheels. If you need more wheels, please enter my shop to buy, thank you! Instructions for use: open:Rotate the button to the upright position and press the button firmly to open,then rotate the button to another position to locked. Take back:Rotate the button to the upright position,push the button to the end and stepping on shoes at the same time,then rotate the button to another position to locked.