1947 Omega 'Jumbo' 38mm Manual Cal. 30T2 Silver Dial 2505-1

Here we have a 1947 Omega 'Jumbo' 38mm Manual Cal. 30T2 (Ref. 2505-1), a monumental and highly elegant piece of mid-century Swiss horology that reflects the clean, expansive design shift of the post-war era. Originally introduced to Omega's international collection in 1946, the Reference 2505 earned its legendary "Jumbo" moniker because its generous case dimensions radically subverted the era's traditional 30–33mm sizing. The 38mm 316L stainless steel case introduces a commanding but incredibly elegant architecture, designed to optimise dial space and wrist legibility. With an ultra-slender case thickness of just 9mm and a sweeping, prominent lug-to-lug length of 46.5mm, its svelte, low-profile body delivers a balanced, comfortable, sophisticated presence on the wrist that slips effortlessly under a formal cuff. The minimalist case architecture features an elegant polished bezel that transitions into long, gracefully downturned lugs to maximise wrist stability. A traditional crown sits alongside a solid, snap-on case back to preserve its vintage dress-watch utility. A high-domed acrylic crystal sits flush over a striking, understated silver dial. The refined dial provides a vibrant, high-contrast aesthetic, utilising printed or applied indices and traditional leaf-style hands that track gracefully across the canvas. Ditching a date window to preserve pure, uncompromised horizontal symmetry, the minimalist layout is anchored by a beautifully scaled, oversized sub-seconds register ticking cleanly above the 6 o'clock position. On the reverse side, the solid steel back protects the historic, mechanical crown jewel beating underneath. Inside lies the magnificent, in-house manually wound Omega Cal. 30T2 movement, a legendary engineering masterpiece revered by vintage purists as one of the finest manual-wind calibres ever constructed. Operating at 18,000 vibrations per hour, this highly reliable, robust 15-jewel mechanism features a straightforward, military-grade architecture built to deliver enduring timekeeping accuracy and a dependable power reserve. This highly exclusive post-war reference comes with a versatile 18mm leather strap, finished with a steel buckle.

This watch is sold as "Watch only" and, therefore, comes with no original Omega box or paperwork. The watch had a 2026 Service. It is paired with an 18mm strap. The watch is from Circa 1947 and is sold in worn, vintage condition. Wear and age can be seen throughout the watch, with an attractive patina on the silver dial, but overall, this is an excellent example of this rare reference. The watch comes with our 12-Months NON-Waterproof Warranty.

It’s crazy to think this watch was made in 1947, just two years after the end of WWII, and Omega was already producing something in a whopping 38mm case. At a time when 30–33mm was far more typical, this must have been quite a shock to the system on the wrist! Nearly 80 years later, though, those proportions feel remarkably contemporary. Add in the beautifully clean dial and legendary Calibre 30T2, and you’ve got a vintage Omega that feels just as wearable today as it must have felt radical back then. I would not hesitate to add this wonderful example to your collection today!

Reference : 2505-1
Movement : Manually Wound Omega Cal. 30T2
Age : Circa. 1947
Year : 1947
Case Size : 38mm
Case Thickness : 9mm
Lug to Lug : 46.5mm
Lugs : 18mm
Condition : Pre-Owned
Box and Papers : None
Case Material : Stainless Steel
Warranty : 12-Months NON-Waterproof Warranty
The wrist model's wrist size is 7inch

Formerly known as the La Generale Watch Co. in 1848, it was founded by Louis Brandt in La Chaux-de-Fonds. When he died in 1879, his sons carried on his dream. In 1880, they moved to 96 Rue Jakob-Stampfli, where they remain today. The brothers produced their first mass-produced calibre, the Labrador, in 1885. Just a few years later, in 1892, they produced the first minute-repeater. In 1903, they renamed the company Omega until 1982, when they officially changed their name to Omega SA. During WW1, Omega watches were used as official timekeepers for the Royal Flying Corps and the US Army. In 1930, Omega and Tissot merged together to form Société Suisse pour l'Industrie Horlogère (SSIH). In 1931, another group was formed - Allgemeine Schweizerische Uhrenindustrie AG (ASUAG). Where SSIH was primarily French-speaking, ASUAG was founded by the more German-speaking members of the Swiss watch industry. In 1948, they introduced the first edition of one of its most symbolic watches: the Seamaster. Omega first introduced the Constellation in 1952. At the time, it was Omega's flagship timepiece. The first models had a Cal. 354 bumper movement in them. Later, in 1955, Omega introduced the Automatic Cal. 50x, followed in 1959 by the Cal.55x (no date) and 56x (date) versions. Many of the Constellations came with pie-pan dials, diamond indexes, and fancy lug configurations. All the gold Constellations of that time have the Observatory of Geneva's hand engraved on the back. The stainless steel and stainless steel/gold versions had a gold medallion on the back with the Observatory of Geneva. The eight stars above the Observatory stand for the many exploits of Omega in the world Chronometer competition. Celebrating the fact that all Constellations are Chronometer Certified. In 1962, when astronaut Wally Schirra wore a Speedmaster on his Mercury Sigma 7 Mission, making it the first Omega watch to enter space. After rigorous tests, NASA used Omega for all their Apollo missions, including the 1969 Moon landing of Apollo 11. Today, Omega is still the first choice of astronauts. In 1969, President Nixon famously said it was “too valuable” and turned down the first-ever all-gold Speedmaster Professional Deluxe. As a response to the ever-growing threat of electronic watches to the manufacturers of mechanical watches, Omega and many Swiss brands such as Rolex and Patek Philippe formed Centre Electronique Horologer (CEH). Prototypes began to appear in 1967, and their production started in 1968. Then, in 1972, Omega introduced the reference 198.030, which included the Omega calibre 1250, a ‘tuning-fork electronic movement which was made under licence from Bulova. Later, we saw a merger of SSIH and ASUAG into SMH, or Société de Microélectronique et d’Horlogerie. This merger took place in 1983. In 1992, the company acquired Blancpain, and in 1998, it officially branded itself from SMH to the Swatch Group. Then, in 1999, they purchased and integrated Breguet into the Swatch Group.