OOSilk Mulberry Silk Pillowcase with Hidden Zipper,Cotton Underside,Standard(20in x 26in) Pale Turquoise Hidden zipper closure at the side prevents slipping.Size: 20 X 26 inches (51 x 66cm) It's absolutely healthy, chemical-free, naturally dyed, no color shading or fading. Mulberry silk values the highest quality among all kinds of silk. Material:upside: 100% 19mm mulberry silk, underside: 100% 300TC cotton in white color. You can enjoy the softest silk and high quality cotton with one pillowcase. The cotton underside is designed to prevent the pillow from slipping off the bed. It's the most natural anti-aging product, as well as hypoallergenic, smooth, soft, breathable, and comfortable. High-quality silk can help prevent hair from becoming knotted and matted, and it can reduce facial wrinkles.