No installation DIY model, no damage to original car circuit  Can put in anyplace in the car to enable the alarm function  Built in air pressure detection to check door open alarm  Built in shock sensor to check car move alarm  With built-in 100dB buzzer for alarming on main unit  The outside 120dB wireless siren can alarm together, the alarm information is send to siren by wireless  The 2 way LCD remote will alarm together with the car lock  Remote and alarm distance is about 1000m (Air distance without building)  Main unit built in high capacity rechargeable Li battery (battery life about 1 month)  New design zinc metal big display LCD remote  Remote have vibration silent alarm function (built in vibration motor)  Real time clock and parking timer (display how many times from locking the car)  Key lock function to protect pressing keyboard by mistake  Carrier modulation: FM - FM technology  Remote use AAA 1.5V Alkaline battery (Battery life is about 3-6 months)  Bright LED alarm indicator  1 one way transmitter add 1 two way transmitter            Main Functions        [Wireless Alarm Siren] Wireless Alarm Siren and No Wires Connect to Car. Free Installation         [Long Alarm Distance] Remote and alarm distance is about 1000m (Air distance without building)         [Alarm System] Built in air pressure detection to check door open alarm, hood open alarm...         [One-Key Car Finder] After button pressed, the siren with 30 seconds alarming         [Two Way Remote Key Control] ARM/DISARM         [Working Frequency] 785Mhz/433.92Mhz