Simultaneous alarm from multi-zones. Sensitivity adjustable: Each zone has 100 sensitivity level. Sound & amp; LED alarm: Both Side LED indicator, easily show where the metal is Automatically count passengers and alarm times Alarm strength indicator on control panel Password protection, only the authorized person can operate Easy assembly : designed with only 2 pieces cables and 8 screws, simply-to-follow instruction Harmless to human body : is harmless with heart pacemaker, pregnant women, magnetic floppy, recording tapes, etc. Using high density fireproof material Program Self-diagnostic when power on, no need initial or periodic calibration Modularization design, easy for maintenance and replacement