1.Choose the size according to your foot length (don't choose the size according to the usual size in your country!!!) 2. Due to manual measurement, please allow 0-0.5cm error in size. 3. If you have any questions, please contact our customer service first, we will help you solve it. Please read our size chart carefully! It can help you choose the right size based on the length of your foot. Please note that if your feet are too long or too wide, please choose a size that is one size larger than usual. please choose Size 40-41, if your foot length is 25.5cm. please choose Size 42-43 , if your foot length is26.5cm. please choose Size 44-45, if your foot length is 27.5cm.