Abstract: In abstract, a preferred embodiment of this invention is a signal device in the form of a coil type spring with an elongated end thereon for fitting under the lip of the door of a rural type mailbox when the door is in the closed position. Intermediate the end of the elongated portion is an enlarged portion preferably in the form of a ball to increase the visibility of the device. The end of the coil spring opposite the elongated portion has a provision for securing the same to the side of the standard rural type mailbox.