The Pillow covers will totally incase the pillow giving it Maximum protection against dust-mite accumulation Stops the accumlation of dust-mites in the mattress 100% Waterproof design Easy to Maintain Unique design allows the body to breath Manufactured with a superior grade of cotton/polyester terrycloth with a thin but strong polyuerthane backing Pillow covers have zipper closure Reduces the occurrence of wheezing congestion sneezing itchy watery eyes headache fatigue rashes and weakened immune system caused by dust-mites & their droppings li>The Rest-Guard covers are quiet. They will not make any annoying crinkling or scraping sounds with every movement Dimensions:21×25