Feature:1. 2 Transmitter and 1 Receiver: Can be used for the front and rear doors. Self generating wireless design, no wiring, no battery.2. Multi Purpose: Not only a doorbell, but also a pager. When a baby and the elderly sleeping alone, and pregnant women need help, they can press it, effectively protect your family.3. IP68 Waterproof Transmitter: The doorbell transmitter is IP68 waterproof and not afraid of harsh weather such as sun and rain, which can extend the service life.4. Long Range Transmission: Long distance signal transmission, strong wireless penetration through the wall, one to one signal pairing, no need to worry about stringing with the next.5. Adjustable Volume: The volume is loud enough to solve the problem that the elderly cannot hear. You can also set one key mute mode to avoid disturbing, adjust volume at will.Specification:Item Type: Self Powered DoorbellMaterial: ABSUses: Homes, villas, hotels, factories, the elderly, patients, pregnant women for one key callType: 2 Transmitter and 1 ReceiverTransmitter Power Supply: Self GeneratedReceiver:Power Consumption: 0.25WRingtones: 38 ringtonesTransmission Distance: Approx. andgt 150m or 164yd, Open SpaceRF Frequency: 433MHzRingtone Volume: 50dB or 1m.Package List:1 x Receiver2 x Transmitter2 x Sticker1 x ManualNote:1. Do not place the product in an environment that is too humid and high temperature!2. Please supply power according to the voltage used. Using other voltages may cause fire and product damage!