The Rolex Daytona 116520 model was introduced in 2000. This popular watch stood for the first totally new in-house movement that the Rolex had designed in more than 50 years: the fully-integrated self-winding chronograph function named the Caliber 4130. 
This Caliber was the result of years of development and was designed to improve accuracy and reliability of the Daytona. Experts were enthusiastic, even if most of the changes took place inside the watch instead of outside and those who did not use the replica watch for its intended chronograph purpose might not even find the difference.
One of the most obvious interior changes to the Rolex Daytona 116520 was the use of a vertical clutch mechanism that couples its movements to the indicators of the watch when activated and is often preferred to the lateral clutch movements used in most watches. The 4130’s new clutch design provided something greatly valued in watches used as chronographs: exact stops and starts of the seconds-hand. This makes the Daytona the perfect “stopwatch” for timing delicate processes, including racing.
The amazing design and traits were also upgraded on this Daytona model. This freed valuable space inside the fake watch so that Rolex could increase the mainspring barrel size, allowing the watch to run longer, together with the size of the balance wheel to upgrade accuracy in timekeeping. In fact, the whole watch was simplified, with 12 screws versus more than 40 in earlier models and 20 percent fewer parts than other watches.
Wider and luminous hour markers, slightly longer lugs and polishing on the top side of the case instead of the brushed finish are all characteristics familiar to Daytona users that will strike a resonating chord with these replica watches. 
The exterior of the Daytona 116520 is very close to that of the 16520. However, there were some subtle but crucial changes made, consisting of moving the seconds indicator from 9 o’clock to 6 o’clock and aligning the hour register with the 30-minute register.
While the Daytona 116520 has made some changes from its earlier incarnations, it is difficult to deny that this watch keeps most of the favorite traditions of Daytona, such as the great chronographic functions and the attractive appearance that have made this watch a favorite for so many years.
