The Keen Revel III is a durable, comfortable hiking boot. The two types of insulation used cuts the chill, and the outsole is designed to hold its ground in icy, slick conditions. The KEEN.Dry waterproof, breathable membrane lets vapor out without letting water in. It features Heat Trapolator to hold warm air in. The Thermal Heat Shield Footbed on the outside keeps the cold out and the heat in.