1The siren can receive signals from other 433MHZ frequency detectors for alarm. 280dB super loud siren, built-in LED strobe light, strong alarm function. 3Low false positive, dual infrared detection components and micro-processing chip, high intelligence and high sensitivity. 4Wireless door magnetic sensor features anti-theft infrared alarm for home door and window, with emergency button. 5Ultra low power microprocessor, dual temperature compensation technology.