【100% Polyester】Satin refers to the weave of the fabric( how it's put together) not the fiber(what it is made of).Ariensky Pillowcases are made of 100% polyester fabric, which has the best softness and easy care, high quality polyester fabric is as soft as silk pillowcases, stronger and more durable than silk pillowcases, smooth and elastic, help you sleep soundly all night 【Good Material for Skin and Hair】Silky fabric prevents irritation to delicate skin, soft and breathable, these pillowcases pamper your hair by reducing tangles and leaving hair smoother, also great for preventing face and neck wrinkles, dry skin. 【Cool and Dry all Night】The silky pillowcase absorbs more heat and moisture than organic cotton, and the silky touch and breathable feel allow you to sleep comfortably and soundly all night.