General description This wireless doorbell is self-powered, requiring no wires or batteries, which protects the environment and saves you money. When the transmitter is pressed, it generates electricity on its own and sends a stable signal to the receiver. This eliminates the hassle of changing batteries and the risk of damaging your wall or doorbell. Technical specifications Transmission power: self-powered Doorbell receiver power supply: AC 110V-230V, 50/60Hz Receiver power consumption: 0.25W Chimes: 38 melodies Volume levels: 4 levels Transmission range: up to 152m (in open area) Operating frequency: 433 MHz Operating temperature: -4°C to 140°C Installation Simply plug the mini receiver into an outlet and attach the transmitter to a wall using the included accessories, which consist of 2 screws and a piece of tape. Usage This doorbell can be used in various settings including homes, apartments, schools, country houses, and offices. It features 38 ringtones and 4 volume levels