Amazing Protection for your Mattress with Advanced Micro-Fiber Technology. Protect the Sleep Environment. Scientific studies have revealed that bed mattresses can harbor millions of dust mites. The dander from these parasites is the leading cause for air borne allergens only second to pollen. The Keetsa Protective Case for your mattress creates a barrier between you and some of the unpleasant organisms that often become resident in unprotected mattress. How This Works: The advanced micro-fibers in our cases actually create a barrier between you, the dust mites and the allergens they cause. The Case completely envelops the entire mattress (all six sides); a zipper allows you to put it on/take it off. Because the fabric is made of micro-fibers, itï¿½s still ï¿½breathableï¿½ so you donï¿½t get the sweat-effect that often comes with old fashioned plastic cases. The micro-fiber fabric is also water resistant and washable. Other Key Facts: We highly recommend the use of The Keetsa Protective Cases as soon as you buy a new mattress. The protectorï¿½s sides are stretchable and can fit up to 12" or 15" loft mattress. For The Keetsa Plusï¿½, The Keetsa Pillow Plusï¿½, The Keetsa Cloudï¿½, The Keetsa Latexï¿½ and Tea Leaf Supremeï¿½, please use the protector with 12" height. For Tea Leaf Classicï¿½ and Tea Leaf Dreamï¿½, please use the protector with 15" height.