Disposable, instant bulk ice packs by Hart Health. Portable and fast acting, instant ice packs are activated through the chemical reaction of ammonium nitrate and water. Bulk ice packs offer instant cold therapy for temporary relief of minor swelling, sprains, and strains. Excellent to have on hand for injuries from work or active play. Bulk instant cold pack box contains 50 individual, large 6″ x 9″ single-use instant ice packs.