Omega 2490

The Omega Reference 2490 (often cataloged as CK 2490-2 under Omega’s early reference system) represents a significant chapter in the brand’s post-war dress watch production. Emerging from the crucible of World War II, this timepiece exemplifies the “Jumbo” Calatrava aesthetic that defined an era when wristwatches transitioned from modest utility to larger, more prominent dress pieces. At 36mm in diameter, the reference 2490 was notably oversized for its era, when typical dress watches measured between 30 and 34mm, earning it the collector-designated “Jumbo” moniker. What makes this reference particularly compelling is its marriage of elegant proportions with one of horology’s most celebrated movements: the Omega Caliber 30T2, a workhorse that powered everything from British military-issue timepieces to certified chronometers.​

Omega CK 2490-2 Jumbo Calatrava Nice Condition Cal 30T2 SC  

History & Production Period

The Omega 2490 emerged during one of the most transformative periods in watchmaking history. Production commenced around 1944, as evidenced by serial numbers in the 10 million range that correspond to this production year. The reference continued through the late 1940s and into the early 1950s, with examples documented through approximately 1954. This production window places the 2490 squarely in Omega’s golden age of manual-wind dress watches, concurrent with the brand’s military contracts that produced over 110,000 watches for British forces during World War II.​​

The “CK” prefix in the full reference designation CK 2490-2 denotes a stainless steel case (“Caisse en Acier” or “CK” under Omega’s pre-1962 nomenclature), though the same movement and case design occasionally appeared in other material configurations. The “-2” suffix indicates a specific case variant within the 2490 family. During this period, Omega was establishing its reputation for precision, with 30T2-equipped watches winning first prizes at the Kew Observatory, Geneva, and Neuchâtel competitions between 1946 and 1951, even relegating Omega’s own tourbillon movements to second place.​

The reference was not marketed under any specific collection name (such as Seamaster or Constellation, which would emerge later), making it part of Omega’s broader dress watch catalog. Production quantities remain undocumented, but the reference appears with sufficient frequency in the vintage market to suggest healthy production numbers while maintaining collectible scarcity.​

1939 Rare Omega Calatrava Military-Style Chapter Ring Patina  

Technical Specifications

The Omega 2490 presents a well-proportioned profile that balances mid-century elegance with modern wearability:

Case Dimensions:

• Diameter: 36mm (excluding crown, measured across the case body)
• Lug-to-lug: 46mm
• Case thickness: Approximately 10-11mm (varies slightly with crystal height)
• Lug width: 18mm

Case Construction:

• Material: Stainless steel (CK designation)
• Shape: Circular with polished finish
• Lug design: Straight, integrated lugs with relatively short projection
• Crown: Unsigned or Omega-signed depending on originality, no crown guards
• Case back: Snap-on construction with smooth or minimally decorated outer surface

Water Resistance:
Water resistance was not a priority for dress watches of this era. The snap-on caseback and lack of gaskets mean these watches offer minimal moisture protection. Modern wearers should treat these as desk-to-dinner pieces, avoiding water exposure entirely.​

Crystal:
Original examples feature acrylic (plexiglass) crystals, which were standard for the period. These develop a characteristic warm patina and can be easily polished, though replacement with period-correct acrylic is common in serviced examples.​

Omega Classic RARE 1940’S 36MM CALATRAVA  

Movements/Calibers

The beating heart of the Omega 2490 is the legendary Caliber 30T2 family, one of the most respected manual-wind movements of the 20th century.​

Omega Caliber 30T2 (1944-1949)

The 30T2 was introduced in 1939 and named for its 30mm diameter base plate, unusually large for the era and allowing for robust construction with improved gear train efficiency. Watches from the 2490 reference’s early production (1944-1949) house this caliber:​

Specifications:

• Diameter: 30mm (13 lignes)
• Jewels: 15 jewels (standard), 17 jewels (upgraded variants)
• Frequency: 18,000 vibrations per hour (2.5 Hz)
• Power reserve: Approximately 44 hours
• Shock protection: Early versions lack shock protection; later variants feature Incabloc
• Hairspring: Breguet overcoil for superior timekeeping
• Regulation: Screw balance with bimetallic compensation (standard); eccenter regulator (Rg variants)
• Features: Subseconds at 6 o’clock, no hacking, no quickset functions

Omega Solid Gold WWII Pilot’s Watch – 30T2 SC movement 

Omega Caliber 30T2 SC (1944-1949)

Some 2490 examples feature the 30T2 SC variant, where “SC” denotes “Secondes Centrales” or center seconds (though subseconds remained more common in the 2490). The SC version adds:​

• 16 jewels (occasionally 17-18 in later specifications)
• Additional bridge for running seconds mechanism
• Slightly increased height (5.1mm vs. 4.05mm for base 30T2)​

Omega Caliber 265 (Post-1949)

In 1949, Omega revised its movement nomenclature, and the 30T2 became the Caliber 265, continuing production through 1963. Later 2490 examples may house this renumbered caliber:​

• Functionally identical to the 30T2
• 15 jewels, antimagnetic properties
• Same 30mm diameter, 18,000 vph frequency, 44-hour reserve
• Shared DNA with calibers 266 (17 jewels), 267 (17 jewels, antimagnetic), and the sweep-seconds 280 series​

Movement Pedigree:

The 30T2’s reputation stems from its elegantly simple yet robust architecture. Unlike contemporary movements that resembled miniaturized pocket watch calibers, the 30T2 featured large, functionally finished plates and wheels, prioritizing durability and serviceability over decorative embellishment. This pragmatic design philosophy made it a favorite among military procurement officers and watchmakers alike, with its ease of assembly and repair still praised by contemporary horologists.​​

The movement’s crowning achievement came at the 1946 Kew Observatory Precision Competition, where it claimed first prize for accuracy and reliability, establishing Omega’s reputation for chronometric excellence.​

Omega Chronometer Chronometre Steel 30t2 RG Chronometer  

Dial Variations

The Omega 2490 appeared with a diverse array of dial configurations, reflecting both Omega’s design evolution and regional preferences during the 1940s and early 1950s. Collectors should carefully examine dial originality, as refinished or “restored” dials dramatically impact value and authenticity.​

Common Dial Styles

Salmone (Salmon) Dials:
Among the most sought-after variations are those featuring warm, salmon-hued dials that develop through natural patina or were originally executed in pink-gold tones. These dials show cream, pink, or peachy tones with gilt (gold-toned) applied markers and hands. Authentic salmone dials exhibit even aging with subtle tonal variations, particularly around printed elements.​​

Silver/Champagne Dials:
Clean, silvered dial surfaces with either painted or applied hour markers represent the most common configuration. These range from stark silver-white to warmer champagne tones, often developing an attractive eggshell patina with age.​​

Sector Dials:
Some examples feature railroad-track minute rings, radial guilloché patterns, or cross-hair designs, popular during the military-watch-influenced design period of the 1940s.​

Vintage Omega Calatrava Coin Edge Sector Dial Steel  

Black Dials:
Rarer in the 2490 reference but documented in related Calatrava-style cases, black dials with either gilt or white-metal hour markers provide dramatic contrast.​

Dial Elements

Hour Markers:

• Arabic numerals (most common): Painted or applied, typically in gold tone
• Raised gold batons or dots: Applied markers soldered to the dial
• Mixed styles: Arabic at 12, 3, 6, 9 with batons at intermediate positions
• Breguet numerals: Occasionally seen on special-order dials

Hands:

• Alpha (straight, tapered hands with pointed tips)
• Leaf hands (broader, curved leaf-shaped hour and minute hands)
• Dauphine hands (faceted, diamond-shaped)
• Blued steel seconds hand (small seconds at 6 o’clock)

Printing and Logos:
Original dials display the Omega logo at 12 o’clock, often with “Swiss Made” at the bottom. Depending on production period and specification, some dials may include chronometer designations or observatory certifications.​

Luminous Material:
Period-correct examples feature radium-based luminous compound (early production) or tritium (later production), appearing as aged, yellowed, or creamy patina on hour markers and hands. Modern replacements using Super-LumiNova are immediate indicators of service intervention.​​

Identifying Refinished Dials

Dial refinishing was common practice during mid-century servicing, making original “untouched” dials particularly valuable. Red flags include:

• Overly bright or glossy finish inconsistent with age
• Perfectly even coloration without natural patina gradients
• Misaligned or poorly executed printing
• Incorrect fonts for Omega logo or text
• Absence of aged luminous material on hands/markers
• Evidence of surface cleaning or scratching around markers​​

Vintage Omega Calatrava Coin Edge Sector Dial Steel  

Case & Bezel Variations

The 2490 case maintains relatively consistent design language across its production run, though subtle variations exist:

Case Characteristics

Construction:
The three-piece stainless steel case comprises a main body, snap-on caseback, and crystal retaining bezel. The snap-on design, while less robust than screw-down constructions, allows for easier servicing access.​

Finish:
Original examples display high-polish case flanks with brushed or polished lugs. Many vintage examples show evidence of polishing from decades of servicing, which can round edges and reduce definition.​

Caseback:
The snap-on caseback typically features:

• Smooth outer surface (most common)
• Inner stampings: case reference (2490-2), material code, serial number
• Some examples include double-beveled edge for aesthetic refinement​

Lugs:
Straight, relatively short lugs integrate smoothly with the case body, creating balanced proportions and comfortable wearability despite the 36mm diameter.​

Crown:
Period-correct crowns may be unsigned or feature the Omega logo. Replacement crowns from servicing are common; originality requires careful comparison with documented examples.​​

Variations and Related

While the 2490-2 represents the primary steel configuration, related references in the Omega catalog from the same period share design DNA:

• CK 2390: Similar case, slightly different proportions
• CK 2505: Larger “Jumbo” variant (38-39mm)
• CK 2791: Seamaster-designated variant with similar case architecture
• CK 2383, CK 2400, CK 2169: Contemporary Calatrava-style cases with shared movement family​​

1940 OMEGA Gents Vintage 14K Rose GF Dress Watch – empressissi 

Bracelet & Strap Options

The Omega 2490 was originally delivered on leather straps, as was standard practice for dress watches of the era. No original Omega bracelets were specifically designed for this reference.​

Period-Correct Options

Original Configuration:
18mm leather straps in black, brown, or cordovan colors, typically secured with simple steel or gold-plated buckles bearing Omega branding.​​

Modern Alternatives:
Collectors today often fit:

• High-quality calf leather straps (18mm width)
• Vintage-style shell cordovan or alligator leather
• Suede or nubuck for casual wear
• Minimalist NATO-style straps for summer wear (though anachronistic)​

Buckle Considerations:
Original Omega-signed buckles add authenticity and value. Modern alternatives should be period-appropriate in style, avoiding contemporary designs that clash with the watch’s vintage character.​

Identifying Original vs. Replaced Parts

Authentication and originality verification present significant challenges with vintage Omega pieces from the 1940s-1950s. Service replacements, well-intentioned restorations, and outright forgeries all exist in the market.​

Dial Authenticity

Original Indicators:

• Natural, even patina consistent with age and storage conditions
• Correct font styles and spacing for Omega logo and text
• Aged luminous compound with consistent yellowing/browning
• Slight imperfections consistent with period printing techniques
• UV light reaction showing age-appropriate characteristics​​

Red Flags:

• Suspiciously pristine appearance (“NOS” or “minty” claims require scrutiny)
• Incorrect dial feet positioning or solder marks
• Modern luminous material (bright green Super-LumiNova)
• Color and patina inconsistent with claimed age
• Evidence of surface refinishing, repainting, or relumination​​

Hands

Original hands should match the dial’s age and patina. Mismatched aging between dial and hands suggests replacement. Correct hand styles for the period include alpha, leaf, or dauphine configurations with appropriate luminous material.​​

Movement

The movement serial number should correspond with Omega’s production dates (10 million series for 1944, 11 million for 1947, etc.). Cross-reference the movement number against the case reference to ensure they’re period-appropriate matches, though movements were occasionally swapped during servicing.​

Watch for:

• Movement with non-matching serial number range
• Replacement parts inconsistent with original 30T2/265 specifications
• Excessive wear or damage suggesting neglected maintenance
• Incorrect jewel count or bridge configurations​

Case Integrity

Polishing:
Over-polishing represents one of the most common condition issues. Original cases feature sharp lines, defined bevels, and crisp edges. Rounded edges, thin lugs, or loss of definition indicate multiple polishing cycles that remove metal and diminish value.​

Case Numbers:
Inside the case back and between the lugs, reference numbers should match: 2490-2 stamped clearly with appropriate serial numbers. Mismatched numbers suggest case swaps or incorrect attribution.​

Crown

Many 2490 examples have replacement crowns from decades of servicing. Original Omega-signed crowns are preferred but difficult to authenticate without extensive comparative research.​​

Collector Notes & Market Context

The Omega 2490 occupies an intriguing niche in the vintage watch market: large enough to appeal to modern tastes, historically significant through its 30T2 movement, yet accessible compared to marquee Omega lines like early Speedmasters or Constellation “Pie Pan” models.​

Market Positioning

Current Value Range (2025):
Based on recent market data, Omega 2490 examples trade in the following ranges:

• Fair condition, service history unknown: $800-1,200
• Good condition, recently serviced, original dial: $1,500-2,300
• Excellent condition, all-original, rare dial variant: $2,400-3,500
• Exceptional examples with papers or chronometer certification: $3,500-5,000+​

Factors driving premiums include:

• Unpolished case with sharp, original lines
• Original, unrestored dial (especially salmone/salmon variants)
• Chronometer-grade 30T2 SC or Rg movements
• Complete service history and period documentation
• Rare dial configurations (sector dials, unusual colors)
• Original Omega-signed crown and buckle​

Collecting Considerations

Appeal:
The 2490’s 36mm diameter translates to approximately 44-46mm lug-to-lug, making it highly wearable for modern collectors accustomed to larger watches. This “Jumbo” sizing was revolutionary for the 1940s and remains perfectly scaled today.​

Movement Prestige:
The 30T2 caliber’s reputation as one of the finest manual-wind movements ever produced adds significant collector appeal. Its military heritage, chronometer achievements, and straightforward serviceability make it a joy for enthusiasts who appreciate horological engineering.​

Availability:
While not rare, finding exceptional all-original examples requires patience. Many have been polished, re-dialed, or fitted with replacement parts over 70+ years of life. Unrestored “survivor” pieces command strong premiums.​

Purchase Pitfalls

Common Issues to Avoid:

1. Refinished Dials: Perhaps the most prevalent issue, dial refinishing was common practice during mid-century servicing. Modern collectors prize original dials, even with patina, over pristine refinishes.​​
2. Over-Polishing: Multiple polishing cycles during servicing remove metal, softening case lines and reducing collector value. Inspect lug thickness and case edge definition carefully.​
3. Mismatched Components: Decades of servicing can result in wrong hands, replacement crowns, or even swapped movements. Verify all components match the period and reference.​
4. Movement Condition: The 30T2’s robustness makes it long-lived, but neglected maintenance leads to worn pivots, damaged jewels, and unreliable timekeeping. Budget for professional service from a watchmaker experienced with vintage Omega calibers.​​
5. Case-Crystal Fit: Improper crystal replacement can damage the bezel or case. Ensure period-correct acrylic crystals are properly fitted.​

Due Diligence:

• Request detailed photographs of dial, case, movement, and case back stampings
• Ask for movement serial number and cross-reference production dates
• Inquire about service history and request recent timing data
• Consider independent inspection by a qualified watchmaker before purchase
• Verify seller reputation and return policies for vintage pieces​

Investment Perspective

Vintage Omega dress watches from the 1940s-1950s have shown steady appreciation, though not the explosive growth of sports models like early Speedmasters. The 2490 represents an entry point into serious vintage Omega collecting, offering genuine horological significance and wearability at prices accessible to enthusiast collectors.​

Long-Term Outlook:
As mid-century design continues its renaissance in contemporary fashion and interest in hand-wound watches grows among younger collectors, well-preserved examples of significant vintage pieces like the 2490 are likely to appreciate steadily. However, originality and condition will increasingly differentiate valuable pieces from common refinished examples.​

1947 Omega Model 2320 – 18K Rose Gold Gentleman’s Dress  

Conclusion

The Omega 2490 represents mid-century watchmaking at its most elegant and unpretentious. Born from the crucible of World War II, powered by one of horology’s most respected manual-wind movements, and sized ahead of its time, this “Jumbo Calatrava” remains as wearable and compelling today as when it first graced wrists in the late 1940s. For collectors seeking an entry into serious vintage Omega ownership, the 2490 offers genuine historical significance, daily wearability, and the satisfaction of winding and wearing a piece of horological heritage. As with all vintage watches, patience in finding an original, well-preserved example pays dividends in both collecting satisfaction and long-term value.