International Code Flags are also called signalling flags. They are a set of flags of different colours, shapes and markings which used singly or in combination have different meanings. The flags include 26 square flags which depict the letters of alphabet, ten numeral pendants, one answering pendant, and three substituters or repeaters.
A merchant flag is defined as the flags flown by the merchant vessels of that country. It is often the same flag as the national flag but a few countries have both national and merchant flags. Available sizes 6’x4′, 4’x3′, 3’x2′