Security adhesive tape
A security sealing tape with a concealed lettering - text OPENED.
A self-adhesive tape has properties identical with a regular packing tape, and in addition, it serves for control of unauthorised penetration into a sealed package. The tape is made so that when peeled off (even partially), the lettering OPENED will appear.
The change is irreversible - the attempt to open the package is still noticeable and the tape no longer adheres.