Natural Material: This pure silk pillowcase is made of 100% high-quality 6A grade mulberry silk, which is skin-friendly, breathable, super soft and smooth. Made of hand-made double stitching, the invisible zipper is the same color as the fabric. Size Color & Zipper: Standard 20*26 inches (51*66 cm) fits most standard size pillows. The updated environmentally friendly high color fastness dyeing makes the color durable and not easy to fade after washing. The invisible zipper design can perfectly fix your pillow without moving. In addition, the invisible zipper will not hurt your skin when you cover the pillowcase. Best for Hair and Skin: Mulberry silk is a natural protein fiber with the same composition as human skin, which makes you feel cool in summer and warm in winter, and can keep facial skin moisturized and anti-wrinkle. The smooth texture can effectively prevent hair from tangling and reduce frizz. Cool Beauty Sleep: Because natural organic silk has the original temperature regulation ability, it can keep you cool all night. Silk fiber contains 18 kinds of amino acids, which have been tested to effectively stimulate the metabolism of skin cells. When you wake up, your skin will be balanced with moisture and enhanced with a newborn baby-like softness. Washing advice and premium service: Dry clean or gently hand wash in cold water (below 30C) with a neutral detergent or silk detergent. Wash dark-colored pillowcases separately and soak for no longer than three minutes.