Pinpoint zones to precisely identify multiple target locations from head to toe. Advanced broadband detection technology: can detect ferrous and non-ferrous articles. Sensitivity adjustable from Level 0 to 200 ; High: Can detect a pin Low: Detect big metal articles such as: knife, gun, and copper, aluminum,zinc ,ignoring metal in belt button, shoes. Shock proof to avoid false alarm,Sound and light alarm Intelligent traffic and alarm counters that calculate traffic flow and resultant alarms. Two LED light bars on both door panels: gives alarm corresponding to the height or human body. Adjustable operating frequencies---eliminate the potential effects from X-ray units, radios and other electrical interference sources. Mix distance between two Walk-thru: 0.3 meters at low sensitivity, 0.5 meters at high sensitivity.  Harmless to pregnant woman and heart pacemaker. Users can choose 6,12 or 18zones freely to work