Description: Each pack contains 1 push button transmitter and 1 US plug-in receiver. Wireless chime doorbell, easy to install, can reach up to around 300m in the open air. Build in anti-interference design, avoid the interference between the laucher and the receiver. Musical doorbell, with 60 melodies and 5 volume leveles. Perfect for homes, offices, hospitals, factories, hotels, stores, mall, office, warehouse, plant, villa etc. Can be an emergency service bell for the old and the weak, provides helps for them timely. Specification: Material: ABS plastic Transmitter Voltage: 12V 23A battery operated(not included) Reciever Voltage: 110V/220V Working Distance: up to 300m(in the open air) Transmitter Size: approx. 72x46x21mm/2.83x1.81x0.82inch Receiver Size: Approx. 92x62x32mm/3.62x2.44x1.26inch Package Includes: 1 Set Wireless Doorwell, including 1 Piece Transmitter 1 Piece US plug-in