A. Dual function: It can be used as both a doorstop alarm and a doorstop. Its high-damping rubber bearing can prevent the door from sliding and help stop unauthorized entry. It serves as a useful guardian. It is suitable for both home and travel scenarios. B. Precautions: The doorstop alarm is suitable for situations where the gap between the door and the ground is between 0.6 inches and 1.2 inches. C. Three sensitivity levels: It has three sensitivity levels - high, medium, and low - which can be adjusted according to individual needs. D. Loud alarm: It emits a loud and shrill alarm sound of up to 120 decibels, which may scare people away. E. Weight: 4.5 ounces. F. Powered by a 9V battery: The doorstop alarm is powered by a 9V battery. Under normal circumstances, one battery can last for about one year. It is quite practical. (Note: The battery is not included.) G. Easy to use: No installation is required. Simply place the alarm behind any inward-opening door (such as doors in your home, hotel, etc.). It is convenient to carry when traveling or staying indoors alone. It is a useful item to have.