NO.1 The size you see is not a standard European or American size, so you need to accurately measure the length of your feet. Then according to your actual length, choose the size according to our size chart.
NO.2 The length of the insole should be 0-1.5cm larger than the length of the foot
As shown in the picture below, measure your foot length accurately.
US: 6.5—foot length: 24CM
US: 7—–foot length: 24.5CM
US: 7.5—foot length: 25CM
US: 8—–foot length: 25.5CM
US: 9—–foot length: 26CM
US: 9.5—foot length: 26.5CM
US: 10—-foot length: 27CM
US: 10.5–foot length: 27.5CM
The above data is for reference only, if the length of your foot is not very standard. You can ask me by email.