Signal flags have long been used for communication between ships at sea. Over time mariners developed a standard set of flags and pennants for this purpose. This International code of signal flag pennants consists of polyester flags. There are 40 individual flags to a set. Each set consists of one of each of the letters A thru Z & one of each of the numerals 1 thru 10. (as shown in the picture above & below). Each set is approximately 40 foot in length and each flag is approximately 9" x 12".