1. 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 discourage unauthorized entry. It serves as a useful safeguard. It is suitable for both home and travel use. 2. 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. 3. Three sensitivity levels: It offers three sensitivity levels - high, medium, and low - which can be adjusted according to personal needs. 4. Loud alarm: It emits a loud and shrill alarm sound of up to 120 decibels, which may scare people away. 5. Weight: It weighs 4.5 ounces. 6. Powered by a 9V battery: The doorstop alarm is powered by a 9V battery. Under normal conditions, one battery can last for about a year. It is quite practical. (Note: The battery is not included.) 7. Easy to use: No installation is required. Simply place the alarm behind any inward-opening door (such as those in homes, hotels, etc.). It is convenient to carry when traveling or staying indoors alone. It is a useful item to have.