Protect the family: The door alarm can add a second level of protective lock to the original door lock, and also has more powerful anti-theft performance. 120db super loud reminder: When touched, it emits a loud sound to remind you that there is an intruder, preventing thieves from sneaking into your room and causing damage to your belongings or ginseng's security. Easy to use: Burglar alarms for doors and windows do not require any special wiring. Just hang it on the doorknob and when you open the door, the alarm will scare away unwanted intruders, leaving you and your home well protected. Travel Protection: Window alarm can be used for travel and hotel accommodation. You can hang this alarm on doors and windows to prevent illegal intrusion. Widely used in home, office, factory. Can be taken with you: Battery powered (battery free), no need for troublesome wires, just hang it directly on the door knob handle, turn on the switch to activate the protection alarm. Note: The data is all manual measurement, please allow 1 - 3cm error, due to the difference in light and display, there will be a certain color difference, depending the physical object received.