The size chart of this style is as follows:
----US Size-----:----Label Size-----Inside Length---
----5.5 M US----:------36------------- 23 cm ---------
----6 M US------:------37------------- 23.5 cm -------
----7 M US------:------38------------- 24 cm --------
----7.5 M US----:------39------------- 24.5 cm--------
----8 M US ----:------40------------- 25 cm ---------
this one is a normal size. It is suggested to take a size larger if the feet are wide or fat.