Features: 
1. Outdoor battery back-up siren wth flashlight. 
2. Double housing: External-3mm plastic PC with UV, internal-0.88mm metal. 
3. Continuous frequency modulated sound. 
4. Tamper protection in 3 ways-screw or cover opening or tearing housing from the wall. 
5. Positive and negtive alarm trigger input. 
6. Siren period can set as follow trigger or 3 min cutoff. 
7. Select from the lamp or xenon. 
8. Alarm by main power failure. 
9. Protecting against totally battery discharge. 
10. Plug terminal for easy installation. 

11. Environmental  immunity.