E. F. Johnson Company Manual. Messenger 40 / Messenger 50 Citizens Radio Transceiver Installation and Operating Manual. Material: paper. Size: 5 1/2" x 8 1/4". Description: orange and white cover; black and white photograph of the Messenger 40; black print: "Messenger 40, Messenger 50, 40 Channel, Citizens Radio Transceiver, Model No. 242-0040, 242-0050, Installation and Operating Manual"; 7 pages.