Rolex model numbers are four, five or six numerical digits long. The first two to four digits describes the type of watch. If the model number is five or six digits long, the second to the last number describes the bezel and the last number describes the metal type the watch is made from.

How can I tell the model of my Rolex?

Rolex model or reference numbers are listed on the certificates Rolex issues, but its also available on the watch case itself. You will have to remove the bracelet to find it. The reference/model number is engraved between the lugs on the 12 oclock side where the bracelet meets the watch case as pictured below.