Feature: No tools needed for installation, no wiring, no expense, no hassle involved with the installation like in expensive alarm security systems. These alarms will mount securely on any surface with included adhesive backing. Specification: Main part: 6cm*3cm*2cm Accessories: 5.4cm*1.3cm*1.1cm Siren loudness: 90 decibels Product power supply: 1.5V 3*LR44 button battery (included in the machine) Packing List: 2*Door and window alarm 1. Product performance introduction Magnetron sensor with high sensitivity; Suitable for security and anti-theft of doors, windows and lockers; The piezoelectric buzzer sounds an alarm; The alarm volume can be as high as 80dB or more; Concealed power switch design; 2. How to use Ensure that when the switch is in the OFF position, install three AG13 button batteries in the correct direction and install the battery door; Fix the host and magnetic box on the cabinet, window, etc. according to the direction. The arrow on the magnetic box points to the host, and the magnetic box should be on the side where the host has a buckle. And the magnetic box and the host should be within the magnetic control distance. Turn the switch to ON, the buzzer starts to sound: when the door, window, etc. are closed, the buzzer stops sounding and the machine is in alert state