Belledorm Premium Blend 500 Thread Count Flat Sheet, Double Ivory. This flat sheet is made from a premium soft blend of 67% cotton and 33% polyester, offering the natural benefits of cotton with the easy-care properties of polyester. It features a sateen weave of highly packed fabric for a silky soft feel, and is easy to wash and maintain. The 500 thread count cotton-rich range combines the luxury of cotton with the benefits of being easy care. A silky sateen weave, woven to feel like cotton, wrinkle-free wash after wash, this high thread count blend is simply the best of both worlds.