Features LOUD-CLEAR WARNINGS: An 80dB sirens ensures you won't missing an alert. STAY ALERT STAY SAFE: Receive instants apps notifications for smog detection. ALERT: An 80db alarm Provides a loud-alert in case of fire, ensuring that you are alerted to potential dangers even if you are sleeping or in a different part of your home or building Compact: The smart smog detector is not one of those ugly saucers on the ceiling or wall. It is a compact thing and looks fashion, the smog detector can be placed inconspicuously. EASY TO INSTALL: Our smog detectors & fire alarms is equipped with screws, stickers, very convenient to install at home or bedroom. Notice: Actual color may be slightly different from the image due to different light effect Please allow 1-3cm deviation due to manual measurement Battery: DC9V alkaline battery (6LR61/9V) (battery not included in shipment) Quiescent current:Alarm current:Operating temperature: 0 DegreeC~+50 DegreeC Relative humidity: Alarm sound: >80dB Battery low voltage alarm: Package List: 1/2/3PCS 80db Smog-alarm