KEEN.DRY waterproof/breathable membranes keep feet dry while dissipating sweat and moisture PFC-free, DWR (durable water repellent) treatment sheds moisture off the surface Waterproof leather uppers with thermal fleece linings keep feet dry and warm KEEN.WARM 100 gr insulation provides additional wintertime warmth -4 F Easily adjustable hook-and-loop tarsal straps let kids secure the fit to their liking, allowing for an easier on and off Thermal Heat Shield insoles with Eco Anti-Odor technology help prevent the growth of odor-causing bacteria Nonmarking rubber outsoles provide traction on wet surfaces