The size is too small, buy the inner length according to the foot length of 1 or 1.5cm

26 inner long 16.5

27 Inner Length 17

28 inner long 17.5

29 inner length 18

Within 30 long 18.5

31 inner long 19.1

32 inner long 19.7

33 inner long 20.3

34 inner long 20.9

35 inner long 21.5

36 Inner length 22