Nikwax Polarproof adds durable water repellency (DWR) to fleece and insulated garments. Nikwax Polarproof adds surface water-repellency which reduces water-absorption, minimizes weight gains, and maintains insulating properties. Nikwax Polarproof lasts several washings and does not need to be reapplied after every wash like other treatments. Even though synthetic insulating fibers naturally absorb little moisture they can hold substantial liquid within the structure of the knit or weave. This significantly reduces the thermal insulating qualities of the garment. With proper cleaning and the addition of Nikwax Polarproof you can improve the performance of your insulated clothing-especially in wet or humid conditions.