This cutting edge pillow cover incorporates Outlast thermo-regulator technology, originally developed for NASA to balance temperature changes experienced by astronauts in space. Added to naturally cooling cotton, the thermo-regulator material works to absorb, store and release heat to create a constant micro climate and keep you at an optimum temperature while you sleep. Ideal for those who are sensitive to temperature variations during the night, or those who sleep on a memory foam pillow, the 100% cotton top offers enhanced breathability and moisture absorption. It proactively provides a specific thermal comfort zone for every individual sleeper, lowering perspiration levels and protecting against the cold. A practical polyurethane base membrane provides waterproof protection, yet allows the skin to breath without the discomfort caused by perspiration. It also acts as a barrier against dust mites and bed bugs to keep your sleep surface healthy and hygienic, whilst the lightweight fabric remains noiseless throughout the night so you're not disturbed by rustling.