RE Aviator - Zac Efron - Baywatch
Efron wears the Aviator model with 23k gold frame. It's hard to see which color lenses are in the frame, it looks most like AGX lenses, but could be grey as well. This model sunglasses can be recognized by their bayonet temples, that are designed to fit comfortably under headgear.
Buy RE Aviator sunglasses online on Amazon.com, Amazon.co.uk, Randolph Engineering, or eBay. There are different sizes, colors and temples available, so make sure you get the pair of your preference. Zac Efron seems to wear the largest variation of the glasses.
Randolph Engineering began as the American dream - two immigrants that started a company making machines to build the parts for other metal eyewear companies. As the others started moving overseas, Randolph started their own sunglass brand and remains the last of the metal eyewear companies made in the United States. Having had a contract supplying the standard-issue glasses to the military since 1982, Randolph is known for their exceptional quality and attention to detail.
Reference: Randolph Engineering Aviator, gold frame
In the same film, Dwayne Johnson wears a pair of gold Sama Syd sunglasses.