100% Mulberry Silk Pillow Cover with Hidden Zipper Standard Size Fabric: 100% Pure Mulberry Charmeuse Silk. 22mm Dermatologists recommend silk pillowcases for minimize wrinkles and prevent dry skin, frizzled hair. Silk is a natual protein fiber with many benefits: Hypoallergenic, natural flame resistant and antimicrobial. with right end seam hidden zipper for better fit. Well made with french seams. Size: Stardard (21"X26.5")