National Allergy Pillow Protectors are made from 100% breathable cotton which promotes a sounder nights rest. Our covers feature an exclusive Zipper System designed to fully encase your pillow. Recommended by Doctors. Keep your pillows clean and protected with the Two-Part System. The auto locking zipper ensures that it will stay closed. An added barrier creates a fabric shield under the zipper closure to doubly ensure there are no gaps. 100% cotton weave is recommended by Doctors nationwide. Fabric is woven so tightly that only air can get through. With a mean pore size of 2.6 microns our breathable fabric keeps you cool comfortable and protected. Pillow encasement is soft to the touch and noiseless when moving around while asleep. This pillow cover is designed to provide an extra layer of quality protection. Cotton zippered pillow encasements are machine washable making them a perfect choice.