The Muck Boot Adults' Outdoor Sporting Wetland Premium Field Boots feature vulcanized rubber uppers and stretch-fit neoprene toplines. The boots are insulated with 100% waterproof 5 mm CR flex-foam with Airmesh linings to provide breathability. Shank and Achilles reinforcement. Cold weather rated for -20°F. Muck Boot Adults' Outdoor Sporting Wetland Premium Field Boots