2Pcs Infrared Beam Detector Burglar Ir Alarm Sensor Automatic Door Light Sensor Alarm System<br> Features<br> Single beam infrared radiation: suitable for anti-theft such as doors and windows, box, fence and so on. Small size, big effect<br> Sealed shell, stronger waterproof: Thanks to the good waterproof design, it can effectively cope with all kinds of bad weather, so that the internal components are not eroded by rain<br> Detection distance 20m: Install to ensure that the emitter and the receiver are on the same horizontal line<br> Stable and reliable anti-interference: using hemispherical optical lens, the beam is concentrated, precise and non-scattering, and the automatic strong light adjustment system can effectively avoid the interference of strong light and car headlights<br> Specifications<br> Light source mode: infrared pulse type<br> Detection method: Beam interruption pick-up type<br> Package Include:2Pcs X Doorbell<br> Note:<br> Due to different personal measurement methods, there will be an error of 2-4 cm, please understand<br> Thanks for your support