Tempilink® Thermochromic Inks provide visible, irreversible indication that a package has been tampered with by heat. Adhesives are generally used to seal packages. Tempilink Thermochromic Inks, printed directly to the package closure, or printed on the sealing tape, provide a visible color change when exposed to heat at select temperatures. This way it is easy to spot which, if any packages, have been tampered with.