Have a look and you’ll find the belong to the reference 18XX series, and the ref. 1803 especially. Released in 1959 and staying in production right up until 1977, it had been the third variant of the gold men watch, the first two premiered following the range’s introduction in 1956 in rapid succession. Measuring 36mm in diameter and throw out of 18k white, red, or yellow gold watch(and platinum quite sparingly), the ref. 1803 was fitted with a bezel and was driven by the Cal. 1555. Back in 1967, the movement shifted to the Cal. 1556, ostensibly identical but beating at a higher frequency vph within the previous vph. A hacking function has been added in 1972, stopping the seconds hand once the crown was pulled out to make setting the time easier. Taken in the Cal, although the two calibers were excellent actors. 1500 series loved by all purists, neither had the mechanism that allows for adjusting the date independently of their hands, a Quickset function. That touch of convenience has been omitted, along with the sheer number of ref. 1803s made over the run that is near means that you could buy them with a 3 band cast in the same metal as the instance, the eponymous President bracelet . This is an incredible amount for an important part of the Rolex story. It was the ref. 1803 that got the Day-Date its unofficial’President’ nickname, even when the watch was photographed on the wrist of Lyndon B. Johnson in 1965. It was the reference that introduced the Crownclasp on the bracelet around the end of the 1960s. But although there are plenty of classic details if you know where to look (pie-pan dialup, acrylic crystal, hollow bracelet links) that the ref. 1803 has aged beautifully. Moreover, the mechanically easy motions have proved themselves to be one of the Rolex has ever made. As a contender for the best worth Day-Date, the ref. 1803 is a definite frontrunner.