Rolex’s Explorer II reference 16550 replaced the beloved reference 1655, which was a modernized version of the brand’s historic Explorer line of wristwatches. The unique design was originally intended for spelunkers (cave explorers), with a fixed, engraved 24-hour calibrated bezel and additional 24-hour hand that permits the wearer to easily know the correct time in the darkness of caves. The 24-hour hand indicates the time on the non-rotating 24-hour calibrated steel bezel. While reminiscent of the 24-hour rotating bezel of the GMT-Master, this watch is not for dual time purposes, but solely for those who are in darkness for prolonged periods of time to enable the wearer to differentiate night and day.

The reference 16550 was a milestone reference. It was introduced in 1985, and was the first Rolex model fitted with a scratch resistant sapphire crystal. Produced for only a few years, white dial examples have become a collector’s favourite due to a manufacturing flaw, with the original white color turning a very pleasing ivory or cream hue over time. Earliest version so the reference provide further intrigue with their attractive “rail” dial configuration found in the perfect alignment of the vertical space between the written text across the two lines of text on the dial at 6 o’clock with “Superlative” and “Officially” words on the left, and “Chronometer” and “Certified” words on the right. In addition to the color change, the dials were made using a glossy, lacquered finish, giving them a porcelain-like look. The white gold applied luminous hour markers complement the dial of the present example, and is different from dials used on the successor reference 16570 with black hour markers.
In original condition, and remaining unpolished, this example stands out with its stunning deep cream dial color. Being sold to benefit The Institute for Digital Archaeology, a non-profit organization promoting digital techniques in archaeology, epigraphy, art history, and museum conservation.