Using patented fabric developed for NASA to help keep astronauts cool in space, this is the pillow that provides a comfortably cool sleeping surface. Available only from Hammacher Schlemmer, millions of invisible microcapsules inside the pillow shell absorb excess heat and move the warmth away from the head and neck until the pillow eventually reaches the ambient temperature. As you shift positions naturally while you sleep, the vacated area of the pillow recovers its cooling properties. The patented fabric covers both sides of the pillow and it is filled with a spiral-crimped polyester that has a loose, thread-like texture for long-lasting loft. The 100% cotton cover is hypoallergenic, removable, and washable.