Mountain Horse(R) Men"s Rimfrost Rider II Tall Boot The winter riding boot that started it all for Mountain Horse is warm, easy to fit and very versatile. Upper in strong Duralon Heat insulating Thermolite(R) lining covered by a soft foam material Strong and durable YKK(R) zipper Durable elastic material inserts along calf area for improved individual fitting Full length Hydro-Tech material walls safeguard the zipper from excessive chafing while providing protection for your saddle Breathable, waterproof HYDRO-Tx membrane prevents water from entering into the footpart up to the zipper Removable insole made of cozy and warm pile lining Heel is fitted with shock-absorbing IPS system to reduce shock impact while walking Built in steel shank for increased stability Stirrup Control System incorporated in the outsole helps maintain correct stirrup position