Using a fabric developed for NASA to help astronauts adapt to extreme temperature fluctuations, these sheets prevent overheating or eliminate chills to create an optimal sleeping climate. Imbedded in the sheets are millions of invisible microcapsules that absorb excess heat when you are hot and release the stored heat when you are cold, ensuring a comfortable bed temperature and humidity. Unlike an electric blanket, the microcapsules adjust independently to an individual's climate, allowing two sleepers with different temperature preferences to remain comfortable throughout the night. The 300-thread count blended cotton fabric is impeccably soft and machine washable. Includes one fitted sheet and one flat sheet, and two pillowcases. White, Linen, Stone, Cornsilk, and Lake Blue. King.