Booklet consisting of 12 pages of typed instructions and two diagrams of Morse machines. Cover contains information on name, guidance to post office officers, issued by, and Post Office Australian Communications insignia. Back cover has stamped numbers at random.

Used by Aggie Armstrong to identify planes over Coffs Harbour during World War II. She did this from the roof of the Forestry Building on the corner of High Street at Coffs Harbour Jetty. Identification was then passed onto the relevant authority.