A common mistake. Many people believe it was a "decoder ring" connected with the show, but it actually was a "decoder badge" that you use to solve the secret message. There were no "decoder rings". Even for the "Little Orphan Annie" radio show it was a "decoder badge". It's believed that the idea that it was a ring originated from a line that Laura Petrie (Mary Tyler Moore) says in The Man from My Uncle (1966); "Rob playing with his decoder ring!"