... /12kgs Pcs per Inner box:12 Features Specification: super door stop alarmThe door wedge alarm is for indoor use only. Set behind any ... in firm contactWith the floor. * When the door is opened, the alarm's metal plate is depressed, Which presses down the trigger ... ON / OFF switch. * Use a 9V battery, not included* The door alarm gives great protection for home, office, orMotel room when traveling.