Rolex Explorer Very rare / early / RED DEPT 6610 1955
Rolex Explorer 6610
Red Depth Dial, 1955 – Original Radium
Some watches are important. Others are rare.
And then there are pieces like this, which sit at the very foundation of Rolex tool watch history.
This Rolex Explorer reference 6610 dates to 1955 and features the highly sought-after and short-lived “Red Depth” dial, a detail that places it among the earliest true Explorers ever produced.
The Red Depth Explorer
The reference 6610 was only produced for a brief period in the mid-1950s and represents a crucial transitional model between the early Oyster Perpetual Explorers and the later, more standardized 1016.
What makes this example exceptional is the red “depth” printing on the dial, a characteristic seen on only a very small number of early Explorers. The red text was quickly abandoned by Rolex, making surviving examples extremely scarce today.
Dial and Lume
• Original black gilt dial with beautiful, even aging
• Correct red depth printing, crisp and clearly visible
• Original radium lume, confirmed
• Hour markers and hands show matching, untouched radium aging
• No relume, no restoration, no cosmetic enhancement
The dial has aged naturally over nearly seven decades, developing a deep, matte character that collectors actively seek. This is exactly how an honest, untouched Explorer from this era should look.
Case and Proportions
• Stainless steel Oyster case
• Strong, well-defined lugs with correct vintage proportions
• Signs of age consistent with careful use, not abuse
• Case appears unpolished or only very lightly polished in the distant past
The case retains its original silhouette, which is critical for early Explorers where over-polishing is unfortunately common.
Movement
Inside beats the original Rolex automatic movement of the period, correct for the reference and generation. The 6610 was among the first Explorers to combine Rolex’s robust automatic architecture with true expedition-grade legibility.
Why the 6610 Matters
The Explorer was born from Rolex’s association with extreme environments, including high-altitude expeditions such as Everest. The 6610 represents the Explorer before it became iconic, when Rolex was still experimenting, refining, and perfecting the formula.
The Red Depth dial is a tangible reminder of that experimental phase, making this reference one of the most historically important Explorers a collector can own.
Condition Summary
• Original 1955 Rolex Explorer 6610
• Rare Red Depth dial
• Original radium lume throughout
• Honest, period-correct aging
• Correct vintage strap fitted
• Collector-grade example