THE ULTIMATE WINTER BOOT. A built-in waterproof and breathable sock keeps feet dry and comfortable. The heat insulating Thermolite lining keeps legs toasty. Boots also feature the Mountain Horse patented Stirrup Control System, steel shank and removable insole. Duralong shaft and YKK Vislon zipper system in back allows for easy entry/exit. Full length Hydro-Tech material walls safeguard the zipper from excessive chafing while at the same time provide protection for your saddle. Durable elastic material inserts along calf area for improved individual fitting. Heel part is fitted with the shock-absorbing IPS system which reduces shock impact while walking. Fabric: Fabric: Duralon/Hydrotech. Lining: Thermolite.