- Brand: OMEGA
- Made: 1941
- Model: Chronograph
- Reference: 2393/1
- Calibre: 33.3 CHRO
- Movement: Manual
- Material: Stainless steel
- Features/complications: Chronograph and square pushers
- Dial: Silvered, two-tone dial with outer printed tachymetric scale and multi-scale with inner minute track with strokes to 1/5th of a second featuring applied steel mirror polished baton hour indices with Roman numerals at 6 and 12 o'clock and subsidiary seconds at 9 o’clock, 30 minute register at 3 o’clock with steel blued syringe shaped hands and centre chronograph hand
- Case dimensions: 37.5 mm
- Bracelet/strap: Leather strap
- Accessories: N/A
- Web reference: 02939
Essay: Developed by Lemania in 1933 the OMEGA manual winding chronograph 33.3 and was a technical marvel for its time and is still revered by collectors today. The 33.3 was far larger than most chronographs for its time and became a favourite of many military forces as well as explorers of the day. The three-piece stainless-steel case is in great condition with well-defined crisp edges to the lugs.
This calibre was initially produced with an independent start-stop reset mono-pusher located at 2 o’clock. However, like the calibre 28.9, a version with two pushers was introduced in 1938: a separate stop-start pusher and a reset pusher integrated into the crown or at 4 o’clock. Anti-shock and anti-magnetic was introduced in 1942 and the name of the calibre 33.3 CHRO changed in 1949 as two lines of chronograph models were introduced: the calibre 170 used to equip non-resistant models and the calibre 171 to equip water-resistant models.
The calibre 33.3 CHRO was regarded as a very precise and reliable movement with 14,000 pieces produced until 1952.