dual function: it can be used as a door guard, door guard alarm, high damping rubber bearing, to prevent the door from sliding and pranks. Protection around you. Available for family and travel. [3 level of sensitivity]: High - medium - low sensitivity. It depends on the distance between the door and the door stopper. [loud alarm]: the intruder tries to open the door, and the corner design will prevent the door from being opened and will activate the 120 db alarm. [9V battery power supply]: The threshold alarm is powered by the 9V battery. Normally one piece can be used for one year. Very convenient. (Note: Battery not included). [Easy to use]: No installation needed] Just set the alarm behind any door (home, hotel, etc.). It is very convenient to carry it when traveling or alone. It must. Especially girls. This door wedge can be easily applied to a closed door and when a door is opened it sounds an alarm to notify you of possible security vulnerability. Features: Dual function: access control alarm, access control, prevent intruders from hitting the wall. High quality: Made from high damping rubber and ABS plastic, it is very convenient to use. Loud alarm: If the intruder tries to open the door, the design from the corner will prevent it from opening and activate the 120 DB alarm to prevent anyone from entering your room and scaring away the bad guys. Widely used: can be used in home, dorm , hotel office, etc. Features: Power supply: 9V battery (not included). Product size 14 cm * 4, 5cm*3.8cm, Contents: 2 door stop alarm.< /p>