SlikSlip 100% Pure Silk Pillowcase 100% cotton Material: 100% 19momme mulberry silk on both sides, soft and smooth. Closure: Hidden zipper design makes the pillowcase hold the pillow perfectly. Big opening and longer zipper allow you fit the pillow into the pillowcase easily. Benefits:The soft and smooth fiber allows the skin and hair to slide over the pillowcase very gently and freely, reducing facial wrinkles and preventing knotted hair. Easy Care: Hand or machine wash in cold water on gentle cycle, do not bleach, hang dry [NATURAL TEMPERATURE REGULATOR]: Pure mulberry silk is a natural temperature regulator which is skin-friendly and moisture to help feel cool in summer and warm in winter. Sleep on silk pillowcases, you will sleep well overnight and enjoy sweet dreams.