This the ORIGINAL Retroworks Secret Window Cipher. It is a basic substitution cipher, where is letter in your secret message is encoded with a corresponding number. An AMERICAN classic! This is the original ring, not the Netflix (or Chinese) knockoff! This is the 2nd in our Secret Decoder Ring Series, the Secret Window Cipher. It is a substitution cipher, where each letter in the alphabet is replaced with a number. The top band spins, allowing the secret window to reveal a number above each letter of the alphabet. To use: Take each letter in your message, and replace it with the number shown in the window above it. MEET AT NOON becomes 15-7-7-22 3-22 16-17-17-16 Send the message to your recipient. They must have a ring (or know the substitutions) to decipher the message. More ring versions may be seen at shopretroworks.com If you are a retail store, please contact us for wholesale availability.