Tamper evident seal is used for security bags. They are classified into Gold Level 4 ，Silver Level 3 and Level 2.

Gold Level 4 Security Tape:
Seals tightly. When torn open, the word “STOP” appears. If the tape is removed at a temperature of -50°C or above, the security word “STOP” also appears and the damage is irreversible. Prevents the use of freezing agents to remove the tape. The wavy coil and security microtext are printed with black water‑soluble ink, which disperses and disappears upon contact with water or solvents. The unique yellow thermochromic line turns from yellow to red irreversibly when the temperature reaches 65°C or above, preventing the tape from being opened by heating or in a microwave oven. It also disperses and disappears upon contact with water or solvents, preventing the use of solvents to open the tape.

Silver Level 3 Security Tape:
The security features are the same as those of the Gold Level 4 security tape, except that it does not have the yellow thermochromic line. Seals tightly. When torn open, the word “STOP” appears. If the tape is removed at a temperature of -50°C or above, the security word “STOP” also appears and the damage is irreversible. Prevents the use of freezing agents to remove the tape.

Level 2 Security Tape:
No mark is left when torn open. Seals tightly. The hot melt adhesive is strong; once sealed, tearing it open causes destructive damage.