6 x 5 3/4 x 1" - 12 oz. Ice-Brix™ Cold Packs. Keep perishables at a constant and desirable temperature for days or extend your shipping times. The ultimate in refrigerant packs. Leak proof, reusable and economical to use. Specially formulated with food safe, non-toxic materials that stay colder than ice. Tested and shown to be the coldest and best gel refrigerant available.