Thermofill is made of elastic and watertight material, and it provides perfect thermal insulation. It's made from a four layer material, with Finnfill fibre as insulating layer, and breathable watertight X-Tex membrane as intermediate layer. The surface material is an elastic and smooth tricot fabric, and the inner lining is fleece. The heavy model is designed to protect against extremely cold conditions. Thermofill insulation is the most distinctive property of Thermofill underwear. Thermofill membrane is developed by the most renowned research institutes and polymere manufacturers. The structure of Thermofill insulation is unique. The material does not lose its insulation capacity even after many times of washing. The Thermofill insulation doesn't break up like most cotton-wool insulating materials, and therefore it doesn't get lumpy or flattened with use or after washing. The material also keeps most of its insulation capacity even when completely wet. The suit has vent holes in the