In 1960s, Rolex decided that the name of its chronograph wristwatches will be changed to Cosmograph Daytona. At that time, the popular Rolex replica chronograph watch was equipped with calibre Valjoux 72 that Rolex purchased from Valjoux. In the later 10 years, Rolex didn’t changed anything of Daytona till the late 1970s. Rolex released Ref.6236 with an important function modified which was the waterproof chronograph pushers.
The chronograph timepieces in early days were only designed to ensure the safety of crown, while the pushers were only protected by with gaskets. Because of the disadvantages of such a structure, many models of Rolex had been damaged for the water entering into the interior of the case. The new white dial copy Rolex Cosmograph Daytona Ref.6263 was water resistant to a depth of 50 meters which was almost 6 times more than the old Ref.6263
Ref.6263 was the one and only model of Rolex that equipped different movements due to different case materials. The manual-winding knockoff watch with white gold case had been equipped with Valjoux chronometer movement, and “Superlative Chronometer Officially Certified” has been set under the position of 12 o’clock. However, the one made from steel was equipped with ordinary calibre Valjoux.