MUCKdry: 100% Waterproof CR-Foam Bootie Construction MUCKcomfort: Breathable Air mesh Lining. Sandwich-fabric lining improves air circulation COMFORT: Cushioned and supportive footbed. Removable 6mm Nitrcel EVA Sockliner 4mm CR Flex-foam which also provides a flexible fit around the leg. Reinforced toe and ankle