Size info:

Size 5 =CN35=225mm (bare feet length) 
Size 6 =CN36=230mm (bare feet length) 
Size 6.5=CN37=235mm (bare feet length) 
Size 7.5=CN38=240mm (bare feet length) 
Size 8.5=CN39=245mm (bare feet length) 
Size 9 =CN40=250mm (bare feet length)
Size 9.5=CN41=255mm (bare feet length) 
Size 10 =CN42=260mm (bare feet length) 
Size 10.5=CN43=265mm (bare feet length)

Details:

heel: about 5.5cm
platform: about 3.5cm
shaft: about 53cm
top opening: about 36cm
med opening: about 33cm
ankle opening: about 23cm

Different people have different leg lengths and different thigh circumferences. Please refer to the shoe measurement data.