iSleep Oxford Series sheet is made from 100% pure cotton which is a natural touch and creates an unforgettable sleeping experience. These cotton sheets feel cool against your skin. Nature has given cotton qualities that make it a smoother, softer, and more comfortable choice. Cotton sheet is a soft, fluffy fiber almost entirely made of cellulose that grows in a protective case around the cotton plant seeds. Being among the finer fibers available naturally, cotton breathes, so cotton sheets feel cool against your skin.