The Mountain Horse Active Winter Rider has a unique YKK Vislon side-fitted zipper that is strong and durable and provides easy entry/exit. Heat-insulating faux fur lining will keep feet and legs warm while the waterproof construction keeps feet dry up to the start of the zipper. The Extensia foot part has been tested to withstand one million flexes in 14F weather. Dirt repellent tread zones on the sole enhance grip in the stirrup. Sturdy and durable YKK zipper for easy entry and exit. Built in steel shank for increased stability. Material: Duralon/Extensia. Insulation: Faux Fur.