The Overton's BioLite Life Vest with Flex-Fit V-Back provides a lightweight fit and increased mobility. The lightweight BioLite shell allows water to dry quickly, while the Flex-Fit V-Back design delivers a comfort fit that moves with you. The vest has heavy-duty slide-release buckles and front zipper. USCG approved type III. Men's Chest Sizes: S(32"-36"), M(36"-40"), L(40"-44"), XL(44"-48"), 2XL(48"-52"), 3XL(52"-56").Vest Lengths: S(22"), M(22"), L(23"), XL(23"), 2XL(23"), 3XL(23").BioLite â An Eco-Friendly Alternative to NeopreneBioLite looks and feels like neoprene, but with many added benefits:• Lighter weight than neoprene. Contains no rubber foam.• Breathable material efficiently evacuates water and lets air through.• More environmentally friendly to produce. No lamination process. No Volatile Organic Compounds (VOCs) which reduce indoor air quality. Flex-fit V-back increases mobility Heavy-duty buckles & zipper closure USCG approved type III | Overton's Men's BioLite Life Jacket with Flex-Fit V-Back