ROLEX Daytona
« Small Daytona » ref. 6240
My favorite reference.
True prototype reference built between 1966 and 1969 from the ref. 6239 dial and case on which ROLEX decided add screw-down pushers (MK0 « millerighe »).
The location of « Daytona » was still very undecided from « small Daytona » as the current example (serial 1,2m) to « Large Daytona » and finally « ROLEX OYSTER COSMOGRAPH » for the latest version before jumping to best seller ref. 6263.