Flowt Type III Extreme Sport Neoprene Life Vest neoprene 1.5 mm thick premium neoprene (Inner & Outer layer). Full body neoprene allows maximum comfort and protection 2 body belts with 1  adjustable belts & YKK buckle & zipper Chest Sizes: Child - 20"-25"; Youth - 24"-29"; SM - 32"-36"; Med - 36"-40"; LG - 40"-44"; XL - 44"-48"; 2X - 48"-52"