Features Magnetic sensor design Highsensitivity magnetic sensor when doors and windows are opened the burglar alarm will remind you that someone has entered your house without permission Loud alarm Super loud up to 90dB or more When someone opens the door or window illegally the relative position of the primary and secondary parts changes the alarm can sound an alarm warn the intruder to leave and remind the owner Easy installation Magnetic sensor switch detects your door or window Easy stick installation and use press the on off button to turn on off 3 pcs button cell batteries are included in the main body tear off the doublesided adhesive on the backpack attach the doorknob alarm to your target position Wide applications The alarm is suitable for doors windows and cabinets to protect against theft Perfect entry warning for homes apartments RVs offices hotel rooms garages and more Specification Siren volume 90de100dB Tested at 30CM Power supply 3 pcs 15V button cell battery included Usage 1 Make sure the power switch is in the OFF position according to the correct direction into the three button batteries and install the battery cover 2 The main machine and the magnet box according to the direction attached to the cabinet window etc The arrow on the magnet box points to the host and the magnet box should be on the side of the host with a buckle And the magnet box and the host should be within the magnetic control distance 3 Set the switch to ON and the buzzer will start to sound when the door and window are closed the buzzer will stop sounding and the machine is in ON mode Material plastic Color white Package Contents 6 x Main Unit 6 x Magnetic Strip The above package contents only other products are not included Note Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing The measurement allowed error is 13 cm