Size reference:

XS: Back length 20CM, chest 30CM
S: Back length 25CM, chest 37CM
M: Back length 30CM, chest 43CM
L: Back length 33CM, chest 49CM
XL: back length 36CM, chest 55CM
 
Note:Due to manual measurement, there are errors in the data, and the size of the error will not exceed 5CM