The fleece-lined, high-performance Arctic Sport is 100% waterproof and features double reinforcement at the instep, heel, and Achilles, and a lightweight EVA molded midsole with a 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 bumper provide optimal traction, durability, and protection on the outside. The stretch-fit topline binding keeps snow out and warmth in, so you tackle any cold-weather task with confidence. Stretch-fit topline binding snugs leg to keep warmth in and cold out 5mm NEOPRENE bootie with four-way stretch nylon,100% waterproof, lightweight, and flexible 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 Shaft Circumference: 17in Boot Height: 13.27in Muck Boot Company Unisex Arctic Sport Mid Boot - Black