APP Notification Warning:Let you know about the situation first. Low Battery reminder:When the smoke detector's battery is low, it emits a short 'beep' sound to alert the userto replace the 85dB Alarm Buzzer:When smoke or fire is detected, the detector's red indicator light starts flashing immediately, and it emits an alarm sound up to 85 decibels.battery. Remote Alarm;Remote alarm combined with APP push, real-time notification through mobile phone APP, users can always know the status of the equipment to the effectiveness of security monitoring. Eco-Friendly ABS Fireproof Material:Excellent resistance and heat resistance Precautions & :360 Integrated Photoelectric Sensor, Full detection of smoke. Wireless Technology:Zigbee 3.0 Transmission Frequency:2.4GHz Sound Pressure Level: 85 dB(A)(at 3 meters in front) Battery Life:Over 3 years(Batteries not included in delivery) Communication Range:s30m indoors Note: The battery is not included in the shipment. The battery model is ZSD20 button battery. Color: White Material: ABS Package Contents: 1 * Smoke Detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.