Clean Rest Premium Water-Resistant, Allergy and Bed Bug Blocking Pillow Encasement, King 100% Microlux Imported MicronOne fabric technology provides a breathable barrier that blocks bed bugs and all micro-toxins larger than one micron like dust mites, mold spores, pet dander and pollen. Patented Zip-N-Click closure prevents bed bug migration. MicronOne MicroLux fabric is water resistant. 10 Year Warranty King pillow encasement fits 20"x36"