The touch of a doorknob will activate this alarm, emitting a 100dB alarm siren. The Door Touch is simple to use – close the door you wish to protect, hang it from the inside doorknob, and turn it on. The alarm will only subside once an intruder has removed their hand from your doorknob. Compact and portable, the Door Touch is ideal for travel. Gloves and other methods of covering one’s hands won’t prevent the Door Touch from protecting you and your loved ones. Features Powerful 100 dB Alarm Activated Via Human Touch - No False Alarms. Easy Installation – No Wires Required Portable & Compact Protection Alarm Works on Wooden, Fiberglass, Composite, and Plastic Doors Having Non-Metallic Frames. DOES NOT FUNCTION on Metal Doors & Doors with Metal Frames Item Dimensions: 3.9” (L)x 2.13” (W)x .9” (D) Requires One 3 AA Batteries (Not Included).