1. Quality steel plate made by punching and shaping 2. Filled with high quality fireproof material 3. One hour fire rating at 1030 degree 4. Massive high security exterior ball bearing hinges 5. 4-8 digits code setting (fixed four sets of digits code under the condition of mechanical lock) 6. Dual alarm is provided for electronic lock series in case of shocking and 3times wrong try. 7. Emergency key and external electric supply for electronic lock series 8. UL approval