The detector is super sensitive and does not report false alarms.It can plug in or use a battery.Fully automatic infrared detection, with strong sensitivity, cannot be affected by light.So the doorbell can be detected day or night.The swivel stand makes it easy to adjust the monitoring angle.You can place it anywhere or mount it on the wall.The host's built-in speaker has a welcome sound volume of 855 decibels, which is the loudest in the host family.16 musical infrared receptions (available day and night) are spread over two levels.The first level is welcome, and the second is dingdong & 16 music and alarm sound (adjustable).Powered by 3 AA batteries, it is energy efficient and durable.(This device does not include batteries).The distance sensing can reach 0-6 meters, and the available temperature is 0-25 degrees.Widely suitable for stores, warehouses, office buildings, factories and homes.Specification:White colorMaterial: ABS plasticHer:The first level: WelcomeThe second level: Dingdong +16 music + sound alarm (adjustable)Battery: 3 AA batteries (not included)Remote detection: 0-6 metersApplicable Temperature: 0-25?Installation and use method:1.Push the battery cover on the back of the doorbell in the direction of the arrow, install 3 AA batteries (alkaline batteries are recommended) and cover the battery cover2.Turn the doorbell switch to voice or alarm level.3.When a guest enters, the welcome doorbell will ring whatever you chose before.Package List:1 x welcome sensor2 basesNote:1.Every time the battery is installed, the product should be self-tested for about 15-20 seconds and then enter the normal working state.2.Sensitivity and volume have been set to standard state, not adjustable.3.If the product produces automatic sound or abnormality, please check the battery power or installation position is correct.4.Avoid directly facing illuminating light/sunlight/reflection/direct exposure, if the ambient temperature is too high (above 30 degrees), the device will appear from far to near,which is normal.5.When the doorbell sound is weak, please replace the battery.The doorbell should be installed in a position where the direct airflow changes significantly (such as air outlet, exhaust fan, electric furnace, etc.), and not installed in the sun or rain.