Silent Call® Doorbell Transmitter with remote button is supplied with a wired doorbell button. It is intended for installation in places where there is no existing wired doorbell or where the existing doorbell is part of an intercom system. The button is installed outside the door with the wire running between the door and the frame to the transmitter which is placed inside the door. Requires (2) AAA batteries (included). Velcro for mounting also included.