To protect the user from the very hot moist heat pack, all moist heat packs must be applied with either a hot pack cover or heavy towel completely wrapped around the pack. The terry cloth hot pack cover allows therapeutic moist heat to penetrate without burning the skin. Hook and loop fasteners keep moist heat packs in place. Soft microfiber finish gives comfortable feel. Covers are machine washable. Measures 18" x 23.5" (45.7 cm x 59.7 cm).