Rolex Explorer II 16550

A checked version of this page, approved on 23 September 2026, was based on this revision.

Rolex introduced the Explorer II 16550 around 1985. It replaced the 1655’s linked 24-hour hand with calibre 3085’s independently jumping local-hour hand, added a sapphire crystal and a nominal 40mm case, and brought the line its first white dial. The 16570 followed around 1989. Auction catalogues sometimes date individual 16550 cases earlier, so the model’s first year is best treated as an introduction date rather than a cutoff for every case.

Core facts

detail	value
reference	`16550`
family	Explorer II
production	introduced around 1985; replaced by the 16570 around 1989; published accounts and lot dates vary
movement	automatic calibre 3085; independent local-hour setting; 27 jewels; 28,800 vph
power reserve	published figures range from about 42 to 48 hours
case	stainless-steel Oyster case, nominally 40mm; catalogues record both 39mm and 40mm
crystal	sapphire, with Cyclops date magnifier
water resistance	100m in specialist specifications
bezel	fixed steel bezel with engraved 24-hour scale
dials	black or white; the white dial is commonly called Polar
lume	tritium on documented original examples
bracelets	published tables list 7206, 7836, 78360 and 93150 combinations; fitment should be checked on each watch
predecessor	Explorer II 1655
successor	Explorer II 16570

Place in the line

The 1655’s 24-hour hand moved with its hour hand, so it showed day or night against the fixed bezel. Calibre 3085 changed that arrangement: its local-hour hand jumps in one-hour steps while the red 24-hour hand continues to show the reference time. With the Explorer II’s fixed scale, the wearer can read one other time zone. The same calibre powered the GMT-Master II 16760, whose rotating bezel can be used to read a third zone.

The 16550 also moved the Explorer II to a sapphire crystal and a larger, 40mm case. Its dial kept the engraved steel bezel but replaced the 1655’s orange arrow hand with a narrower red 24-hour hand and Mercedes-style hour and minute hands. The 16570 followed with calibre 3185 and continued the black-or-white dial choice.

Production dates and serials

Specialist histories usually place the 16550’s introduction in 1985. They differ on the end of production: Monochrome gives 1988, while European Watch Company and Sotheby’s use 1989. Auction catalogues include earlier estimates for individual cases. Antiquorum describes serial B431181 as circa 1985 and case 8584610 as circa 1984; Christie’s catalogued case 8399062 as manufactured in 1983 in its account of an unusual dial. These dates are the auction houses’ descriptions, not a complete production sequence.

Specialist histories and auction estimates place the run in the mid-to-late 1980s. Rolex’s general serial chart gives overlapping year estimates; the auction cases below add reference-specific examples without fixing a serial cutoff. See Serial numbers for the chart and 16550 anchors.

Movement notes

Calibre 3085 first appeared in the GMT-Master II 16760 and later powered the 16550. It has 27 jewels and beats at 28,800 vibrations per hour. Published power-reserve figures differ: Monochrome gives 48 hours and European Watch Company gives 42. The Movement reference records the broader specification and its source limits.

The crown’s intermediate setting advances or reverses the local hour hand in one-hour steps. The date changes as that hand crosses midnight; the movement does not have a separate direct quickset-date position. This is the first Explorer II arrangement that lets the wearer change local time without stopping the 24-hour hand. Sotheby’s catalogues identify 27 jewels on several individual 16550 watches.

Rolex calibre 3085 movement — Calibre 3085.

Dial map

Black dial

The black dial has a glossy finish, applied hour markers with white-gold surrounds, tritium plots, a red 24-hour hand and Mercedes-style hour and minute hands. Some examples have a “rail” layout, with the two C letters in the chronometer text aligned vertically. Rail describes the printing; it is separate from dial color.

Some black dials show fine cracks in the glossy lacquer, usually called spider dials by collectors. Auction and dealer photographs document this surface condition on individual watches. The cracks describe condition; originality and factory history require other evidence.

White Polar dial

The white dial introduced the Polar version of the Explorer II. Early examples use white-gold surrounds around the luminous plots; the 16570 that followed is generally distinguished by black surrounds. Specialist and auction records also show late 16550 dials with black surrounds, though they leave the factory changeover date unsettled. A dial’s fit depends on the watch’s service and ownership history as well as its color.

Cream and rail dials

Some white dials have aged to cream or ivory. European Watch Company describes a defect in the white dial paint; Sotheby’s catalogues describe the cream tone as aging. European Watch Company attributes the creaming to a paint defect; Sotheby’s describes the color as aging. Neither gives paint chemistry or a factory correction date. Italian collectors use panna, meaning cream, for this color.

“Rail” refers to the vertical alignment of the C in CHRONOMETER with the C in CERTIFIED. It appears on black as well as white dials, so cream and rail are separate features. Auction catalogues identify cream rail examples from around 1985 through 1988, though their dates remain estimates for individual watches.

Cream dial example on a Rolex Explorer II 16550 — Cream dial example.

Nipple-style dial

Christie’s and Antiquorum have catalogued three 16550s with raised, cup-shaped luminous markers, described as “bicchierini” or nipple-style dials. Christie’s attributes case 8399062 to two Beyeler dials requested for the 1982 Basel fair, with one later fitted to that watch. Antiquorum called case 8584610 a prototype in 2020, then described case 9376077 as a prototype in 2021. In the later catalogue, Antiquorum said it had seen three such examples on the market, including the Christie’s and 2020 Antiquorum lots. Antiquorum’s count is a report of market sightings. The two auction houses present the dial origin as an attribution, rather than citing a Rolex production record.

Case, bezel and crown

The case is stainless steel, with drilled lugs and crown guards. Rolex-related reference guides describe a 40mm case; Sotheby’s measured one example at 39mm and another at 40mm. The difference may reflect measuring practice or individual catalogue work, so 40mm is the nominal size rather than a guarantee for every surviving case.

The bezel is fixed and engraved with a 24-hour scale. The sapphire crystal and date magnifier distinguish this generation from the acrylic-crystal 1655. Specialist specifications give 100m water resistance. The case and movement share their broad architecture with the contemporary GMT-Master II, while the Explorer II retains its fixed bezel.

Bracelets and end links

The Vintage Rolex Field Manual lists six combinations for the 16550:

7206 with end-link 58
7836 with end-link 580
78360 with end-links 580, 593 or 501B
93150 with end-link 501B

Antiquorum’s 2020 prototype lot also records a 78360 bracelet with 501B end links. These are published fitments and an individual example; original delivery still needs watch-specific evidence. A clasp code dates the bracelet, not the watch head.

Auction examples

The lots below record catalogue dates, dial labels, movements and measurements on individual watches:

source example	catalogue description	what it documents
Christie’s, lot 217, case 8399062	“bicchierini” prototype; catalogue says manufactured in 1983	Christie’s account of two special dials requested for Basel 1982 and one fitted to this watch
Antiquorum, 2017, case B431181	circa 1985, ivory rail dial, calibre 3085, 40mm	an early catalogue description of a cream rail example
Antiquorum, 2020, case 8584610	circa 1984, black prototype nipple dial, 78360/501B bracelet, 40mm	an auction-house prototype attribution and a documented bracelet pairing
Antiquorum, 2021, case 9376077	circa 1986, black prototype nipple dial, calibre 3085, 78360/501B, 39mm	a third auction example and Antiquorum’s report of three market sightings
Sotheby’s, 2020, case 9,673,878	circa 1987, cream rail dial, calibre 3085 with 27 jewels, 39mm	one catalogue’s case measurement and dial description
Sotheby’s Geneva, 2020, case R828043	circa 1988, cream rail dial, calibre 3085 with 27 jewels, 40mm	a second rail example with a different case measurement
Sotheby’s, 2024, case R387466	circa 1987, cream rail dial, calibre 3085 with 27 jewels, 40mm	catalogue lists a K7 bracelet clasp; that stamp dates the bracelet, not the case

Each auction entry records one house’s description of a specific watch. Taken together, the lots illustrate catalogue dates, measurements and prototype attributions; production chronology and dial-to-serial rules remain unresolved.

Related references

Gallery

Explorer II 16550
Black dial detail
White Polar dial
Cream dial example
Calibre 3085

Sources