The reference number of the first Rolex Daytona to have screw-down chronograph pushers was 6240.
Introduced in 1965, Reference 6240 added Rolex’s “Oyster” configuration to the manually wound Cosmograph line. Its screw-down crown and pushers improved water resistance by sealing the openings used to wind the watch and operate its chronograph.
The answer is often confused with References 6263 and 6265, which also had screw-down pushers but came later, during the transition to Rolex’s updated Calibre 727. Reference 6239 was earlier: it helped establish the Daytona name and racing-oriented design, but retained plain pushers.
Reference 6240 is especially significant because it was an experimental and transitional model. Early examples may show varied dial details, and surviving watches are highly sought after by collectors. The “Daytona” name itself was not consistently printed on the earliest dials, adding another layer to the model’s complicated history.