Pls ignore Amazon Size Chart and refer to our size chart below S: US34, M: US36, L: US38, XL: US40, XXL:US42, 3XL: US44 You also can use flat measurements to get your fit.Chest width S: 40'', M: 42'', L: 44'', XL: 46'', XXL:48'', 3XL: 50'' size, refer to the ways on the pic below