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: M， L， XL，2XL，3XL

>ASIA SIZE Shoulder / Chest / Length / Sleeve

M: 40cm/ 95cm/ 64cm/ /
L: 42cm/ 100cm/ 66cm/ /
XL: 44cm/ 105cm/ 68cm/ /
2XL: 46cm/ 110cm/ 70cm/ /
3XL: 48cm/ 115cm/ 72cm/ /