Slip® pure silk products are made using slipsilk™. Specially-commissioned (which means you won’t find it anywhere else!) and made to our exacting standards, developed and refined for over ten years to provide the ultimate combination of shine, thickness, softness and durability. Slipsilk™ has been tested by an independent third-party lab and shown to absorb significantly less face cream and create 43% less friction, on average, versus cotton pillowcases. (Compared to widely available cotton pillowcases with a 220-360 thread count).