Reference:2240

Bubbleback → 2240

Mat silver dial with applied gold indexes, Antiquorum Geneva 1995

Antiquorum catalogued two 32 mm steel Oyster Perpetuals as ref. 2240 in 1995. Both have centre seconds and a self-winding, 19-jewel movement. The entries support the reference’s place among early Oyster Perpetual automatics, but they do not show a reference engraving or caseback. The Bubbleback classification remains probable rather than confirmed.

Arthur Johnson & Sons attributed a domed-back Rolex Oyster to ref. 2240 in two March 2026 listings of the same watch. The photographs show the case profile and movement number 31706; they leave the case number and reference engraving out. The dial is signed “Rolex Oyster,” without “Perpetual.” Its case has Bubbleback form, while the reference attribution remains unverified.

Core facts

detail	value
reference	2240
family	Oyster Perpetual; Bubbleback classification probable, not fully documented
production	no documented range; Antiquorum dates individual examples to the 1930s and 1940s
case diameter	32 mm in both Antiquorum records; Arthur Johnson gives no diameter
case shape	tonneau
case	steel tonneau, polished and satin-finished on the two Antiquorum examples; screw-down back and crown
caseback profile	not shown on the Antiquorum watches; domed on the Arthur Johnson watch attributed to ref. 2240
bezel	smooth, polished
crystal	material not stated in the catalogues
crown	screw-down
winding	self-winding
seconds	centre seconds
movement	9¾ lignes, rhodium-plated, 19 jewels, lever escapement, monometallic balance, self-compensating Breguet balance-spring. No caliber number published
case materials	stainless steel on all three attributed watches
dials documented	two Antiquorum watches wear different mat-silver layouts; the Arthur Johnson attribution has a silvered Roman sector dial; original fitment unproved
dial designations	"Oyster Perpetual, Superlative Chronometer, Officially Certified"; "Oyster Perpetual Chronomètre"; "Rolex Oyster"

Where it sits in the line

Both Antiquorum entries describe a 9¾-ligne, 19-jewel automatic movement with centre seconds, and list screw-down backs and crowns. The catalogues do not name a caliber or describe the case as two-piece.

The 1873 and 2765 are manual-wind Oysters with flat backs in their cited records. Their tonneau outlines resemble the 2240 examples, but the catalogue descriptions distinguish their movements and casebacks.

Production outline

The auction record consists of two Antiquorum lots in 1995 and two Arthur Johnson listings of one watch in March 2026. Antiquorum dated its Hong Kong example to the 1930s and its Geneva example to the 1940s. The catalogues do not publish case numbers. Arthur Johnson recorded a £800 hammer on 7 March and reoffered the same watch on 14 March, when the hammer was £680; the reason for the reoffer is not stated.

These are catalogue dates for individual watches, not a production range. All three attributed watches are steel. None of the cited lots gives a case number that could test its date against serial-number guidance.

Movement notes

Antiquorum describes the 9¾-ligne movement as rhodium-plated, with 19 jewels, lever escapement, monometallic balance, self-compensating Breguet balance-spring and centre seconds. Both entries call it self-winding. The catalogues do not supply a caliber number.

A centre-seconds 600-series Perpetual, such as Cal. 630, is a possible identification, not a confirmed one. Arthur Johnson’s photographs show movement number 31706 but no caliber marking. The watch’s reference engraving is also outside the published views.

Dial map

The three attributed watches have different dials. The auction photographs document each watch as catalogued; they do not establish original delivery configuration.

The Geneva example has a mat-silver dial with applied gold indexes and radium-filled bâton hands. “Oyster Perpetual” appears below the coronet, with “Superlative Chronometer Officially Certified” above six o’clock. The Hong Kong example is also mat silver, with painted Arabic numerals at every hour, an outer minute track with five-minute markers, “Chronomètre” above six, and bâton hands described by Antiquorum as radium-filled.

The Nottingham watch has a silvered dial with a faint sector pattern, applied Roman numerals at even hours and batons at odd hours, a printed outer minute track, gilt leaf hands and centre seconds. Its dial surface is heavily crazed. The signature reads “Rolex Oyster.”

Rolex’s 2021 brochure dates the phrase “Superlative Chronometer Officially Certified” to the late 1950s, when it first appeared on Datejust and Day-Date dials. Antiquorum dates the Geneva watch to the 1940s, so its dial inscription and catalogue date conflict. The available lot images do not resolve whether the dial was replaced or refinished, or whether the watch was misdated.

• 
  Hong Kong lot: painted Arabic numerals
• 
  Arthur Johnson listing: Roman sector dial

Case, bezel, crystal, and crown

Antiquorum describes both watches as 32 mm steel tonneau cases with polished and satin finishes, screwed backs and crowns. Its catalogue calls them waterproof. The listings do not specify the crystal material or internal case construction.

Domed, coin-edged screw-down back on the Arthur Johnson watch attributed to ref. 2240; no reference engraving was shown

The Arthur Johnson photographs show a pronounced domed back in a coin-edged screw ring. The auctioneer reports that its crown does not screw down. The case number and reference engraving are not visible, so these features cannot be assigned securely to ref. 2240.

Christie’s technical catalogue for a ref. 2764 calls it a Bubbleback without describing the back profile. That wording is a useful comparison for auction descriptions; it does not establish the 2240’s case construction or caliber.

Bracelets, end links, and clasps

The cited photographs show all three attributed watches on leather straps. They do not document a factory bracelet or end-link fitment for ref. 2240.

Auction record

Venue	Date	Lot	Dated by catalogue	Dial	Estimate	Result
Antiquorum, Geneva (Hôtel des Bergues)	1995-04-22	304	1940s	Mat silver, applied gold indexes, bâton radium hands	CHF 2,600–2,800 (USD 2,200–2,400)	Not published
Antiquorum, Hong Kong (Hotel Furama Kempinski)	1995-06-14	29	1930s	Mat silver, painted Arabic numerals, bâton radium hands	HKD 15,000–18,000 (USD 2,000–2,200)	Not published
Arthur Johnson & Sons, Nottingham	2026-03-07	7353	Not dated	Silvered sector, applied Roman numerals, gilt leaf hands	Not published	GBP 800 hammer recorded; reoffered one week later
Arthur Johnson & Sons, Nottingham (The Saturday Auctions)	2026-03-14	7287	Not dated	Silvered sector, applied Roman numerals, gilt leaf hands	Not published	GBP 680 hammer

Antiquorum publishes estimates but no realised prices for its two lots. Arthur Johnson’s photographs show the same watch in both March listings: lot 7353 on 7 March and lot 7287 one week later. The reported £800 and £680 hammers belong to successive listings of one object.

The two Antiquorum catalogues identify separate ref. 2240 watches with self-winding, 9¾-ligne, 19-jewel movements and centre seconds. Arthur Johnson’s lot records a domed-back watch attributed to ref. 2240; the published views do not verify that reference.

Related references

• Bubbleback 2764: Cal. 620N "Super Precision"
• Bubbleback 2940: centre-seconds contemporary
• Bubbleback 3131: the 1936 two-piece case transition
• Oyster Chronometer 2765: the manual flat-back that shares the list but not the mechanics
• Oyster Royal 1873: manual flat-back Oyster

See also the Bubbleback family index, movement reference, bracelet & clasp guide, and serial numbers by year.

• 
  Geneva lot 304
• 
  Hong Kong lot 29
• 
  Arthur Johnson lot 7287
• 
  Caseback on the attributed watch

Sources

• "Rolex Oyster Perpetual, Superlative Chronometer, Officially Certified, Ref. 2240", Antiquorum, 1995-04-22
• "Rolex Oyster Perpetual Chronometre, Ref. 2240", Antiquorum, 1995-06-14
• "Arthur Johnson & Sons Lot 7353 — Rolex Oyster 'Bubbleback' attributed to ref. 2240", Arthur Johnson & Sons, 2026-03-07
• "Rolex - an Oyster 'Bubbleback' wristwatch, ref. 2240, stainless steel case, automatic movement", Arthur Johnson & Sons, 2026-03-14
• Rolex, Superlative Chronometer Certification brochure, 2021
• "Buying, Selling, & Collecting: The Rolex Bubbleback And Why It Still Matters", Hodinkee
• "A Collector's Guide to Rolex Bubbleback Watches, From 1931 to the 1950s", Robb Report
• "List of Bubbleback models (user w-v-m)", RolexForums
• "ROLEX, OYSTER PERPETUAL BUBBLE BACK REF. 2764 CALIFORNIA DIAL, STAINLESS STEEL SELF-WINDING WRISTWATCH WITH SWEEP SECONDS", Christie's
• "Rolex Bubble Back History: A Comprehensive Collector's Guide", Bob's Watches