Numbering of Omega calibres (post 1999)

Numbering of Omega calibres (post 1999):

Structure

Since 1999, all newly introducted calibres are numbered using the same structure. Calibres introduced before 1999 were allocated an arbitrary number, without any codification.

All new calibre numbers consist of a four-digit figure. The meaning of the first and second digits can be seen in the table below...

Table

De coding table for the first and second digits

Note: A different codification applies to the second digit for chronographs (Green Column)

First Digit Means:

0
Old numbering (with codification)

1
Old numbering (with codification)

2
Mechanical

3
Mechanical Chronograph

4
Electronic

5
Electronic Chronograph

6
Autoquartz

7
Autoquartz Chronograph

8
Reserved (not yet allocated)

9
Reserved (not yet allocated)

Second Digit Means:

0
Hour, minutes

1
Hour, minutes, date

2
Hour, minutes, small seconds

3
Hour, minutes

4
Hour, minutes, seconds

5
Hour, minutes, seconds, date

6
Other displays

7
Reserved (not yet allocated)

8
Reserved (not yet allocated)

9
Reserved (not yet allocated)

(Chrono) Second Digit Means:

0
Second & minute counters

1
Second, & minute counters, date

2
Second, minute & hour counters

3
Second, minute & hour counters, date

4
Flyback

5
Flyback, date

6
Other displays

7
Reserved (not yet allocated)

8
Reserved (not yet allocated)

9
Reserved (not yet allocated)

The third and fourth digits are used to differentiate between calibres with the same functions and have no specific meaning.
The letter after the calibre number indicates the version of the calibre. A new version of the calibre becomes necessary if the technically modified spare parts are not interchangeable. (A = 1^stversion, 2^ndversion, etc.).

So a Calibre 2500B is the Second version of a 2 = Mechanical, 5 = Hour, Minutes, Seconds, Date;

And a 3303 is a: 3 = Mechanical Chronograph, with 3 = Second, Minute & Hour counters, and date.

Special Thanks to Shaun Thorton for passing this information along...
-- Chuck