These Men's Boulet boots were built to keep you warm. Boots with 400-gram thinsulate have a temperature rating of 35 to 50 degrees Fahrenheit for cold weather. Thinsulate insulation is made of unique microfibers or fine fibers that work by trapping air molecules between you and the outside. The more air a material traps in a given space‚ the better it insulates you from the cold outside air. Because the fibers are finer than the fibers used in most other synthetic or natural insulation‚ they trap more air in less space‚ which naturally makes Thinsulate a better insulator. The Stockman heel keeps your feet secure in the stirrups. Boulet boots are renowned for their unsurpassed quality. Every pair is carefully handcrafted respecting the old tradition of three generations. Most adult boots are entirely leather lined for greater comfort. The famous Boulet brand is sold in North America and Europe and are known by cowboys around the world for their durability, comfort, and being first in fit.