The Explorer's second generation, and the one that made it thin. It took calibre 1030, a bidirectional-winding automatic that sat flatter than the movement of the 6350, so the domed caseback of the early Oyster Perpetuals went away. Everything else carried over — 36mm case, 3-6-9 dial, Mercedes hands — and passed intact to the 1016 that followed.
Reference record
Production
1955–1959
Model
Explorer
Case material
Stainless Steel
Case size
36mm
Movement
Automatic
Calibre
Cal. 1030
Dial colours
Black
Market value band
$18k – $50k
Notable
—The 3-6-9 layout was established by the 6350; the 6610 continued it rather than introducing it.
—Calibre 1030 was in the contemporary Submariners too — the 6536 and 6538 used the same movement.
What the specification implies
—The move to calibre 1030 is the defining specification change from the 6350, and the flatter caseback follows from it.
Common questions
When was the Rolex 6610 produced?
The 6610 was produced from 1955 to 1959.
What movement does the Rolex 6610 use?
The Rolex 6610 runs the Cal. 1030, an automatic movement.
How do I check a Rolex 6610 with Watch Safe?
Look up the watch's serial number in the Watch Safe registry to see whether a record exists or a theft flag is attached. A registry search identifies records for a specific serial; it does not authenticate the watch. Authentication is performed in person by an independent expert authenticator, and Watch Safe records and publishes the result.