The Bogs Classic High Adjustable Calf is constructed with 100% waterproof 7mm Neo-Tech waterproof insulation, and BOGS Max-Wick to quickly evaporate sweat, this boot will keep your feet warm and dry even at temperatures as low as -40°F/-40°C. The adjustable boot shaft ensures a comfortable fit no matter your calf size, and the durable rubber sole has a self-cleaning tread for long-lasting wear.