The Wireless Infrared Doorbell is a set of infrared sensing electronic guard, which includes one wireless transmitter and one wireless receiver. The transmitter makes use of infrared sensing technology to detect almost every movement and send a signal to the receiver from up to 100m away. You can clearly know your family members who are leaving and coming, and help to detect unwanted people. Features: - Color: White. - Material: Plastic. - Size: Approx. 17.5 x 11 x 7.5cm. - Support Welcome/Doorbell/Alarm mode - Welcome mode applicable to business services, doorbell mode uitable for family courtyard and door, alarm mode use as burglar alarm system. - Large range of Infrared induction - Up to 100 meters detection range. Specifications: - Power Supply: Receiver host: 3 x AA battery(not included); Infrared curtain: 1 x 9V laminated cell (not included). - Frequency: 315MHz. - Transmission Distance: 100m(Open Place). - Sensor Range: 3-7m. - Receiver host voltage: DC 3V. - Infrared curtain voltage: DC 9V.