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 touching the alarm. [Loud alarm]: intruders try to open the door, the wedge-shaped design will prevent opening and activate a 120dB alarm[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 notifying you of a 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 activate a 120 alarm dB, 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.