Muck Boot Men's Arctic Sport Steel Toe Work Boots - The Arctic Sport Steel Toe is an extreme conditions work boot. It keeps you working at your best when mother nature is at her worst. The Arctic Sport features a stretch fit topline binding that keeps the warmth in, a 5mm neoprene bootie with four way stretch nylon that is 100% waterproof, a fleece lining and the protection awarded by a steel toe construction. Stretch-fit topline binding snugs leg to keep warmth in and cold out 5mm NEOPRENE bootie with four-way stretch nylon 100% waterproof Fleece lining 2mm thermal foam underlay added to the instep area for additional warmth EVA molded midsole with contoured footbed MS-1 molded outsole is rugged, aggressive and durable for maximum protection and stability Meets ASTM F2413-11 M I/75 C/75 EH Style: ASP