On a goodwill transit through the Panama Canal, the US Frigate Constitution hosted the Boy Scouts of the Canal Zone.  The ungummed, official business, Naval penalty envelope required no postage to the United States.

Simple one line Scout Camp Post ("Cserkész-Tábori-Posta") applied to this card at the camp of Scout Troop 309.  Entered the postal system at the Szigliget Postal Station ("Ügyn") with proper 10 fillér rate to Balatonboglár, Hungary.