2pcs Infrared Beam Detector Burglar Ir Alarm Sensor Automatic Door Light Sensor Alarm SystemFeaturesSingle beam infrared radiation suitable for antitheft such as doors and windows, box, fence and so on. Small size, big effectSealed shell, stronger waterproof Thanks to the good waterproof design, it can effectively deal with all kinds of bad weather, so that the internal components are not eroded by rainDetection distance 20m Install to ensure that the transmitter and receiver are on the same horizontal lineStable and reliable antiinterference using a hemispherical optical lens, the beam is concentrated, accurate and nonscattering, and the automatic strong light adjustment system can effectively avoid interference from strong light and car headlightsSpecificationsLight source mode infrared pulse typeDetection method Beam interruption acquisition typeThe package contains 2pcsDoorbellNoteDue to different personal measurement methods, there will be an error of 24 cm, please understand.Thank you for your support.