slip Queen Pillowcase in Petal. slip Queen Pillowcase in Petal. The beauty secret of celebrity hairstylists, dermatologists and beauty experts. Slip pure silk products are made using slipsilk, developed and refined for over ten years to provide the ultimate combination of shine, thickness, softness and durability.. In Petal - fits queen/standard size pillows (20 x 30) with zipper closure. Made from grade (6A) long fiber mulberry silk, with a thickness of 22 momme and enforce the strictest quality guidelines, including non-toxic dyes.. Cinically shown to visibily improve: The apperance of fine lines Skin hydration, texture and smoothness Skin radiance and luminosity. Hypoallergenic. Use up to eight hours daily for maximum results. Machine washable on a cool/delicate cycle - delicates wash bag recommended. Sold as a single. SLIP-WU57. 810046984963. 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.