Double function: can be used as a door stopper and a door stopper, its strong shock-absorbing rubber bearing can prevent the door from sliding and prevent the bad guys. Protection around you. Can be used at home and while traveling. [3 Sensitivity Levels]: High, Medium, Low Sensitivity. It depends on the distance of the door that touches the alarm. [Loud alarm]: intruders try to open the door, the wedge-shaped design will prevent the opening and activate an alarm of 120 dB [Powered by 9V battery]: The door stop alarm is powered by 9V battery, 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 (home, hotel, etc.). Very convenient to take with you when traveling or staying indoors alone. A must around you. Especially for girls. This door stopper can be easily applied to closed doors, when the door is opened it will activate an alarm warning you of possible security intrusion. Features: Double function: door stopper and door stopper to prevent intruders from entering and prevent the handle from hitting the wall. High quality: Made of 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, will prevent anyone from entering your room and scare away the bad guys. Wide Usage: Can be used at home, dorm, office, hotel, etc. Features: Power supply: 9 V battery (not included). Dimensions: 1.5 x 5 x 1.6 cm. Contents: 2 door stop alarms.