Polartec® Thermal Pro®: The primary insulation layer among experienced outdoor enthusiasts for nearly two decades, Polartec® fabrics are available in a variety of unique textures and weights designed specifically to enhance performance in a variety of environs. Polartec® Thermal Pro® was developed to bring a wider variety of styles and performance functionality to synthetic fleece technologies. Thermal air pockets retain heat without restricting breathability to give you consistent warmth. Open air channels mean minimal mass, which drastically reduces fabric weight and increases compressibility for better packing and storage. Polartec® Thermal Pro® fabrics are also durable and fast drying.