The Infrared Doorbell is a set of infrared sensing electronic guard, which includes one transmitter and one receiver. The transmitter makes use of infrared sensing technology to detect almost every movement and send a to the receiver from up to 280m . You can clearly know your family members who are leaving and coming, and help to detect unwanted people. Features: - ColorWhite - Shell material: durable hard plastic. -Size: 7x3.5x1.5cm -Support Welcome/Doorbell/Alarm mode - User have 3 mode to choice.Welcome mode applicable to ,Doorbell mode uitable for family courtyard and door,Alarm mode use as burglar alarm system. -Adjustable sound volume - 4 level of adjustable sound volume,press the button and adjust1-2-3-4-3-2-1 , but volume of the alarm mode sound is not adjustable -2 choice of power supply - Receiver host: 3*AA battery(not included) or micro USB; Infrared curtain: 3* AAA battery(not included) or micro USB .Power-saving design so that its battery have long lifetime -36 songs can be choose - Various model and voice can be applied in different occasion,user can choose songs for their need to build festival atmosphere,cause the purchase desire and so on. -Large range of Infrared induction - Up to 280 meters range. Specifications: Power Supply: Receiver host: 3*AA battery(not included) or micro USB; Infrared curtain: 3* AAA battery(not included) or micro USB Frequency: Transmission Distance: 280m(Open Place) Sensor Range: 2~8m Volume: 4 level Brightness: 4 level Working Environment Temperature: -10 degree centigrade~ degree centigrade Receiver host using AA battery(not included) or micro USB power supply, infrared curtain using AAA battery(not included) or micro USB power supply. Package list: 1 x Infrared welcome doorbell 1 x Receiver 1 x User manual 1 x Bag of Screws