a mailbox signaling device for rural mailboxes for indicating when the mailbox has been opened to insert delivered mail or retrieve outgoing mail . the device , which is preferably supplied in kit form for do - it - yourself installation , includes a signaling member , preferably including a portion coated with high visibility paint , pivotally secured to the mailbox for swinging movement between raised and lowered positions and a flexible connector extending from the signaling member , through the mailbox interior , to a releasable connection at the door of the mailbox . opening the door releases the connector allowing the signaling member to fall indicating such door opening .