The Original Muck Boot ASP000A-10 Arctic Sport Men's Boots, 10, BlackArctic Sport Hi Boot is warm enough for the coldest outdoor days, durable enough for the most rugged conditions. The fleece lined, high performance Arctic Sport is 100% waterproof and features double reinforcement at instep, heel and Achilles, and a lightweight EVA molded midsole with contoured footbed for supreme comfort and cushioning. A 2mm thermal underlay adds extra insulation on the inside, while the rugged MS 1 molded outsole and wrap up toe