The black Daytona W series Ref 16520s' made between 1994 and 1995.
Rolex used an organic varnish called Zapon to protect the dial.
Unrecognized at that time, the lacquer did not provide sufficient coverage and, over the years, the silver dials have started to oxidize, turning a definite brown colour as they react with UV rays and heat.
Even more importantly for collector, the changes do not stabilize and continue to take effect the older the watch gets.
This is what we called Patrizzi dials. They are unique, in the world of classic Rolex, unique equals to expensive!
The above one is one example of W series (1995), yet going into very "Patrizzi"!
The changing of colour takes time, years and that degree of brownie dial will add value to the watch to a degree of TWO times?
So this is another fun collector item of Daytona Zenith 16520 Series "W" after you have the last series A or P...
Price range between HK$220,000 to HK$550,000 assuming full set and AA condition. (Price of Today 25 June 2019)
HK Snob