There is a sensitivity adjustment switch on the side of the door plug alarm. Toggle the switch H button and place it in the door gap. When the door is opened, the pressure sensor will sound an alarm, or if you place the door and window, it will sound as long as you touch the product itself. Sound; the M key and the L key have the same function and effect, which is suitable for the door gap, and then the pressure senses the iron plate when the door opens, and an alarm is issued. 2. When the power switch at the rear of the door plug is turned off, a 120 decibel high-pitched alarm will sound