Rolex, Sea-Dweller, "Rail Dial, Great White Mark II", ca 1979

In 1967, Rolex launched its first-ever Sea-Dweller model, the Reference 1665, which was characterized by its two red lines of text reading "SEA-DWELLER" and "SUBMARINER 2000," earning it the nickname the Double Red Sea-Dweller. However, later versions feature the so called "Great White" dial without the red text lines. Although the earlier versions are more widely recognized, the "Great White" models are indeed rare, as they were only in production for approximately half a decade.

Among these, the Rail Dial is especially sought after by collectors for its unique and rare design. Manufactured by Stern, one of the defining features of the Rail Dial is its vertical "rail" between “superlative chronometer” and “officially certified”. Additionally, the Swiss designation reading "T Swiss T < 25" is exclusive to the Rail Dial and not found on other Sea-Dweller dials.