* The door stop alarm is for indoor use only. * Use a 9V battery. * With ON/OFF switch. * Insert the alarm at the base of your door, making sure the non-skid pad on the bottom of the alarm is in firm contact with the floor. * When the door is opened, the alarm?s metal plate is depressed, which presses down the trigger anchor and sounds the alarm. * To silence the doorstop alarm, turn it OFF. * Alarm sound: 120dB.