The Zentek pillow case cover is made the polyester mesh covering the 40% mPCM fabric. Available in 3 sizes, standard,queen' and king. The standard size is 20" X 26", the queen is 20X 30, the king 20" X 36". and is used underneath the pillow case.. to provide for all the temperature extremes you may experience in your head and neck area. Yes, is amazing for hot flashes! Wash cool and hang to dry.