The mountaineering Rolex and the watch that grew out of it: eleven references across two lines that share an origin and then diverge. The Explorer runs unbroken from the 6350 of 1953 to the 39 mm 214270, through the 1016's twenty-six years in the middle. The Explorer II forks away in 1971 with the orange-arrow 1655, built for people working without daylight, and becomes a dual-time watch when the 16550 arrives. Two lines, one file.
| REFERENCE | PRODUCED | CALIBER | CASE | RATED |
|---|---|---|---|---|
| Rolex 6150 | c. 1953–1955 | A296 | 36 mm | 50 m |
| Rolex 6350KEY | c. 1953–1955 | A296 | 36 mm | 50 m |
| Rolex 6610KEY | c. 1955–1959 | 1030 | 36 mm | 50 m |
| Rolex 1016KEY | c. 1963–1989 | 1560/1570 | 36 mm | 50 m |
| Rolex 14270 | 1989–2001 | 3000 | 36 mm | 100 m |
| Rolex 114270 | 2001–2010 | 3130 | 36 mm | 100 m |
| Rolex 214270KEY | 2010–2021 | 3132 | 39 mm | 100 m |
| Rolex 1655 "Freccione"KEY | 1971–1984 | 1575 | 39 mm | 100 m |
| Rolex 16550KEY | c. 1984–1989 | 3085 | 40 mm | 100 m |
| Rolex 16570 | 1989–2011 | 3185/3186 | 40 mm | 100 m |
| Rolex 216570 | 2011–2021 | 3187 | 42 mm | 100 m |
"c." marks a production window documented as approximate — including by Seiko's own archive.