[Dual function]: can be used as door stopper alarm and door stopper, its highly cushioned rubber bearing can prevent the door from slipping and prevent bad guys. Protection around you. Can be used at home and when traveling. [3 sensitivity levels]: high - medium - low sensitivity. It depends on the distance between the door and the door stopper. [Loud alarm]: Intruders attempt to open the door, the wedge-shaped design will prevent it from opening and activating a 120 dB alarm. [Powered by 9V battery]: The door stop alarm is powered by 9V battery, one part can be used for one year under normal circumstances. Very convenient. (Note: battery not included). [Easy to use]: no installation required] Just place the alarm behind any door (house, hotel, etc.). Very convenient to take with you when you travel or stay alone. A must have for you. Especially for girls Product This door wedge can be easily applied to closed doors, when the door is opened, it will trigger an alarm warning you of a possible security breach. Features: Double function: door stop alarm and door stopper to prevent intruders from hitting the wall. High Quality: Made of high damping rubber and ABS plastic, very convenient to use. Loud Alarm: If an intruder tries to open the door, the wedge-shaped design will prevent it from opening and activating a 120dB alarm, prevent anyone from entering your room and scaring off bad men. Widely used: can be used at home, dormitory, hotel office and more. Features: Power supply: 9 V battery (not supplied). Dimensions: 1.5 x 5 x 1.6 cm. Content: 2 door stop alarms.