The present reference is considered a rarity by vintage Rolex collectors because of its peculiar “Snake dial”. It is well known that dials of watches tend to react to sunlight, black dials tend to “tropicalize” and develop a brown patina, prized by collectors. This particular Mk 5 dial has develop a strange texture, possibly due to the protective lacquer coating reacting to strong light over time. This texture, which recalls the texture of snake skin has resulted in the watch earning the nickname “Snake Dial” Triple Six.

This very timepiece was featured in Rolex Submariner Story, a seminal tome on the history of Rolex diver’s watches by France and Guido Mondani and Lele Ravagnani. The watch is featured on Page 191 of this book, first published in 2010.

Also known as the “Triple Six” among Rolex aficionados, the Reference 16660 was a transitional model and was introduced in 1978 and produced right up to 1989 before being replaced by the Ref. 16600. Between 1978 and 1983, Rolex had both the original Ref. 1665 and the Ref. 16660 in production.

Among the key upgrades from the Ref. 1665, the Triple Six had a thicker case and better water resistance (4,000 feet instead of 2,000 feet), a larger helium escape valve (HEV), a sapphire crystal instead of plexiglas, and a uni-directional bezel instead of a bi-directional one.