Worn by: Adam Sandler as Howard Ratner
Reference: Audemars Piguet Royal Oak
Brand: Audemars Piguet
Howard Ratner's first watch is an Audemars Piguet Royal Oak Chronograph ref. 25860ST, which gets stolen within the first seven minutes by loan sharks in his Diamond District office. The prop master Catherine Miller specifically requested a period-correct model for 2012 rather than using a brand new watch, adding authenticity to Ratner's character as a jewelry-store owner and hustler.

Source: https://www.hodinkee.com/articles/adam-sandlers-three-watches-in-uncut-gems
Worn by: Adam Sandler as Howard Ratner
Reference: Rolex Day-Date
Brand: Rolex
Ratner's second watch is a Rolex Day-Date with a red dial and an iced-out bracelet with diamond-encrusted bezel—the epitome of aftermarket customization and the Reference Featured on the film's poster. The watch was loaned by an actual Diamond District jewelry-store owner who provided about 15 iced-out Rolexes for consideration, worth roughly $250,000 total. This watch is stolen when Ratner is chased at his daughter's school play, beaten, and stripped of everything before being locked in the trunk of his own car.
Source: https://www.hodinkee.com/articles/adam-sandlers-three-watches-in-uncut-gems
Worn by: Adam Sandler as Howard Ratner
Reference: Breitling Chronomat
Brand: Breitling
After losing two watches to theft, Ratner's final watch is a large Breitling Chronomat with gilt numbering on the bezel and the signature Chronomat crown. The watch makes a brief but crucial appearance as the Boston Celtics beat the Philadelphia 76ers behind a strong Kevin Garnett performance, with the camera focusing on the Breitling on Ratner's wrist as he unlocks the door to his shop in the film's climactic sequence.

Source: https://www.hodinkee.com/articles/adam-sandlers-three-watches-in-uncut-gems