1.if you can not understand our size description or you are doubt about size , Please contact with us . you also can remark your height ,weight and other measurements in order, e.g 180cm /80kg or 5'11''/175lb. 2.Normally, the shirt size should be bigger than your body size. you can check your usual shirt. if your body chest is 100cm, we suggest you choose shirt with 104cm or 108cm.