Connected Doorbell and Video Door Phone -Door Knob Alarm Generic Brand Highlights Door Knob Alarm Description: You just need to hang the alarm in the door handle/knob; when someone opens the door or touches the door handle on one side or the other, it will trigger a loud alarm sound to signal the presence of an intruder. Works as a burglar alarm, alarm siren up to 120 dB. Easy to use and install, no wiring required (requires DC 6F22 9V batteries, not included); simply hang the alarm on the inside of your door handle. Perfect travel alarm and ideal for home, hotel, dorm, etc. Sensitivity may be affected by the composition of the door handle. Specification: Material: Plastic Size: Approx. 10x5.5x2.5cm/3.94x2.17x0.98inch Power: DC 6F22 9V Package includes: 3pcs Door Handle Alarms Note: Since the above size is measured by hand, the size of the \'actual item might be slightly different from that shown above. Due to lighting effects, monitor settings etc. There could be a slight difference in the color tone of the pictures and the actual item.