120DB: Security door alarm with 120DB to detect entry, prevent children and babies from leaving the house, protecting your home or office security.Simple installation : Ultra-thin door and window alarm, can be easily installed on any door or window, which will not damage your furniture.High Accuracy: The doorbell alarm is suitable for children who sleep alone, the elderly and pregnant women, with high accuracy and no false alarm.Easy to use: when opening the door, the main machine will make an alarm sound of 120 DB. When the door is closed, the alarm sound will stop.Low Voltage Warning: You'll easily know when to replace the batteries with the door alarm's low battery indicator, don't don't worry about it not working.