slip Groom Pure Silk Sleep Mask Bridal Collection in Groom. slip Groom Pure Silk Sleep Mask Bridal Collection in Groom. Designed to help you get your uninterrupted beauty sleep.. Made from 100% highest grade long fiber mulberry silk. Anti-aging, anti-sleep crease, and anti-bed head. Includes 1 x groom sleep mask with black piping. SLIP-WU39. 810046983294. 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.