The HEAVY-DUTY VALVE TAMPER SEALS are both deterrents and indicators of the unauthorized opening or closing of the sprinkler system valves. They meet the installation requirements of NFPA 13 and inspection requirements of NFPA 25 for sprinkler systems too. (Attach seals to valves in a manner that the valves cannot be operated without breaking the seals.) Each seal is stamped with a 7-digit serial number that can be recorded to show who performed the installation, inspection, or maintenance. IMPRINT SEAL is available with 3-lines, 8 characters per line. Minimum 5000. Matted in strips of 10 for ease-of use. Sold in boxes of 1000.