In 1963, production of the COSMOGRAPH began with the reference 6239, initially with a VALJOUX 72B movement, and identical to that of the 6238 models. In 1965, the first model with screw-in buttons was produced. TheDAYTONAboom started in Italy in 1985, when a magazine published on its cover the photo of G. Agnelli, arm resting on the mast of a boat, wearing a classic 6263 with light-coloured dial. A simple photo that would breath new life into a model that for 22 years had never really found its public.
- Movement: Valjoux 7750b1 Automatic, mechanical, self-winding.
 - 25 Jewels
 - Functions: hours, minutes, seconds, working chronograph
 - Size: diameter 40 mm, height 12.5 mm
 - Case: Solid Stainless Steel 316L
 - Dial: Meteorite Grey Dial, silvered Roman numerals, three subdials
 - Genuine scratch-resistant, pressure-proof sapphire crystal glass.
 - Strap / Bracelet: Genuine Leather with Deployant Buckle
 - Smooth sweeping second hand,exactly like the real Rolex
 - Double locking security clasp
 - Screws in the links not pins
 - Serial/band number on last link/lugs
 - Serial number between the lugs
 - Serial number on clasp
 - Power reserve approx. 42 hours.
 - Weigh the same as authentic
 - Replicated to the smallest detail.
 - No docs and box.