Pls ignore Amazon Size Chart and refer to our size chart on our seller page: This vest is slim fit, pls order one size bigger if you want regular fit, S: US36, M: US38, L: US40, XL: US42, XXL:US44, 3XL: US46 You also can use flat measurements to get your fit size, refer to the ways on the pic below: Chest width S: 38'', M: 40'', L: 42'', XL: 44'', XXL:46'', 3XL: 48'' 65% Cotton 35% Polyester, Fully lined