NWT Slip Limited Edition Pure Silk Pillowcase in bronze. Slipsilk™ is specially-commissioned and made to our exacting standards, developed and refined over ten years to provide the ultimate combination of shine, thickness, softness and durability. We use the highest grade (6A) long fiber mulberry silk, with a thickness of 22 momme and enforce the strictest quality guidelines, including non toxic dyes. Slipsilk™ has been scientifically tested by an independent third-party lab and shown to significantly reduce friction and absorb significantly less face cream. *Compared to widely-available cotton pillowcases with a 220-360 thread count.