Rolex Daytona: What is the meaning of the Greek letter “Sigma” placed outside the Ts?

Rolex Daytona: What is the meaning of the Greek letter “Sigma” placed outside the Ts?

This is an important question between the collectos of Daytona: What is the meaning of the Greek letter “Sigma” placed outside the Ts?

Sigma is a conventional sign among the various dial-makers and the watch manufacturers, indicating that the hour-markers or the dial plate (and thus also the hands) are in precious metal.
 
You can find more information in the book Rolex Daytona Story
Rolex Daytona Story Sigma
And receive each week a custom selection of articles.