I'm afraid that you regard the size as Euro Size and US Size.please do not follow system size chart !!!
if you want make a very correct choice you should choose by the size chart at the Second image !!!

>available: XS，S， M， L， XL，2XL

>ASIA SIZE Shoulder / Chest/ Length / Sleeve
XS: 39cm/ 98cm/ 60cm/ 60cm
S: 41cm/ 100cm/ 62cm/ 61cm
M: 43cm/ 102cm/ 64cm/ 62cm
L: 45cm/ 106cm/ 68cm/ 64cm
XL: 46cm/ 108cm/ 70cm/ 66cm
2XL: 47cm/ 110cm/ 72cm/ 67cm