Product Information:

Size      Length of Back   Chest Circumference     The Suitable Weight For Reference(1/2 kilo)

XS                 20                                   30                                              3-4

S                   25                                  35                                              4-6

M                  30                                  40                                              7-9

L                  35                                  45                                              9-11

XL                40                                  50                                              10-13

All the sizes is CM,it is measured by hand,there will be 3-5cm random error probably.