Featuring HydroHeat™ technology which absorbs moisture from the air and releases it as clean, deep-penetrating, moist heat. Simply microwave for 30 seconds and apply 3-5 minutes a day to relieve dry eye and improve meibomian gland function. Also aids in the treatment of sty, TMJ, sinus pressure, allergies, tension and stress. May also be frozen and applied cold to relieve swollen, puffy eyes. Washable and reusable. Anti-microbial material won’t grow mold or fungus, unlike seed or grain compresses.