slip Queen/Standard Pure Silk Pillowcase in White. slip Queen/Standard Pure Silk Pillowcase in White. Not all silk pillowcases are created equal. Like an 8-hour beauty treatment every night, slip Pure Silk Pillowcase is made using slipsilk, developed and refined for over ten years to provide the ultimate combination of shine, thickness, softness and durability. Loved by dermatologists, celebrity hairstylists, and beauty experts, silk fibers are significantly less absorbent than many other fibers, so they can help keep your skin's moisture and expensive face and hair products where they belong - on your face and hair. slipsilk helps to reduce friction, allowing skin to glide along the pillow while reducing extra pressure on creased skin. It can also help reduce friction on hair throughout the night, preventing pulling, tangling, creasing, and damage, so you can wake up in the morning without bed head.. In White - fits queen/standard size pillows (20 x 30). Made from 100% highest grade (6A) long fiber mulberry silk with a thickness of 22 momme. Envelope-style closure. Machine washable & non-toxic dyes. Use up to eight hours daily for maximum results. Machine washable on a cool/delicate cycle - delicates wash bag recommended. Use a pH neutral liquid detergent and/or fabric softener. SLIP-WU4. 853218006094. In 2003, slip Co-Founder and CEO Fiona Stewart was prescribed acne medication which resulted in extremely sensitive skin and thinning hair. Her dermatologist suggested sleeping on a silk pillowcase. Unable to find one, she sourced the best silk she could find and wrapped it around her pillow. The results were dramatic and immediate, she's never looked back. She had stumbled upon a long-forgotten beauty secret - and slip was born.