Ayiyoy 100% Mulberry Silk Pillowcase with Silky Underside Polyester White The up side is 100% Grade A long standard mulberry silk in 19mm 400 thread count, the underside is made with 100% polyester in white color, which the purpose is more hydrating than cotton Size: 20 X 30 inches (48 X 74cm), usually fits standard and queen size pillows, you can measure you pillow size before buy(does not contain pillow core) Envelope design, slightly offset side entry, Our proprietary design allows this pillowcase to be used as a sham or pillowcase High-quality silk can help prevent hair from becoming knotted and matted, and it can reduce facial wrinkles Wash in cold water; mild soap lay flat to dry. Don't soak or wring, wash silk separately