Standard Size! (One per package). 80/20 cotton/poly terry top: provides added natural comfort. Advanced Microbial Barrier: prevents the transference and buildup of harmful microbes such as dust mites, mold, mildew, fungus and bacteria. Doctor Recommended: for allergen reduction, asthma, allergies, eczema and incontinence. Prevents Pillow Stains. Zipper Closing. Waterproof/ Cool Comfort.