The mechanical energy generated by pressing the button is converted into sufficient electrical energy to send a radio signal to the wireless doorbell, triggering the chime. The LED light signal indicates to you, even in silent mode, that visitors are at the door. Maintenance-free operation: By converting the mechanical energy from the button press into electricity, the need to purchase and replace batteries is eliminated. Easy installation: The installation is extremely quick, with no settings required, as the doorbell and call button are already paired. Suitable for all residential homes: The wireless range of 150 meters in open space gives this doorbell an advantage over standard commercial solutions.