The Snowgem winter boots feature a seam-sealed, waterproof construction that keeps your feet dry thanks to the 3M Thinsulate insulation, and they are made from environmentally friendly Litem leather. Whether you're shoveling your car out or snowshoeing with family, the removable comfort insoles with odor control will keep you from sweating. The more air a material holds in a given space, the higher its insulation value. The microfibers in Thinsulate insulation are much finer than other fibers, allowing them to "trap" more air in less space, providing excellent insulation.