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 280m away. You can clearly know your family members who are leaving and coming, and help to detect unwanted people. Features: - Color: white.- Shell material: durable hard plastic.-Size: 7x3.5x1.5cm-Support Welcome/Doorbell/Alarm mode - User have 3 mode to choice.Welcome mode applicable to business services,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 detection range. Specifications: Power Supply: Receiver host: 3*AA battery(not included) or micro USB; Infrared curtain: 3* AAA battery(not included) or micro USBFrequency: 433MHzTransmission Distance: 280m(Open Place)Sensor Range: 2~8mVolume: 4 levelBrightness: 4 levelWorking Environment Temperature: -10~33Receiver host using AA battery(not included) or micro USB power supply, infrared curtain using AAA battery(not included) or micro USB power supply.Packing list: 1 x Infrared welcome doorbell1 x Receiver1 x User manual 1 x Bag of Screws