How do I translate OMEGA's model numbers?
Current OMEGA model numbers follow a mostly straightforward convention. A model number, such as 2831.80.08, can be interpreted digit by digit. The following list covers only the variations for the Seamaster Professional, GMT, and Professional Chronograph watches. Other OMEGA lines use the same sequence, but the numbers represent different options. Even here, you will see odd variations between some of the codes for the Chronograph versus the Pro. Newer variations, like the 1998 Titanium Pro Diver and the GMT also get designated somewhat less obviously. Only certain combinations of these options are available.
How to read OMEGA Seamaster model numbers
for the Aqua Terra, Professional Diver, GMT, and Chronograph
Warning: Codes are not used consistently by OMEGA, use this table only as a rough guide
1 Product 2=Seamaster
2 Case / Bracelet 1=Gold (yellow or white), 2=Steel (Pro 2000 bracelet) OR Titanium (Chronograph), 3=Stainless Steel and Gold, 5=Stainless Steel (Pro Diver, GMT, or Chrono) or Titanium (Pro Diver), 6=Red Gold w/Strap (Pro Diver), 8=Stainless Steel w/Strap, 9=Seamaster Pro 2000 w/Strap, 0=Seamaster Pro 2000 w/alternate bracelet (USA)
3 Size / Movement Size/movement codes are not consistent, especially with the new models introduced in 2000.
0=Coaxial, 3=Pro Diver full-size Automatic or GMT Automatic, 4=Pro Diver full size Quartz, 5=Pro Diver mid size Automatic, 6=Pro Diver mid size Quartz, 7=Ladies Auto, 8=Ladies Quartz, 9=Chronograph Automatic
4 Bezel Bezel codes are not consistent by color - they vary by model and case material.
1=Blue (Steel Pro) OR Gold (Gold Pro) OR Brushed Steel (Titanium Pro Diver), 2=Polished Steel (Steel Pro) OR Gold (Two-Tone Pro) OR Blue (Gold Pro) OR Polished White Gold (white Gold Pro, silver dial limited edition 150th Anniv. Pro) 3=Plain (Aqua Terra), Steel w/black numbers (Titanium Diver) 4=Black (Steel GMT or Steel Pro) OR Yellow Gold (Yellow Gold GMT), 5=Steel w/blue numbers (Steel Diver), 6=Gold (Titanium/Tantalum Chronograph), 8=Polished Steel (Steel Chronograph or GMT) OR Gold (Two-Tone Chronograph) OR Blue (Titanium Chronograph), 9=Blue (Steel Chronograph)
5 Dial 2=White, 3=Silver, 5=Black, 7=Special (such as Mother-of-pearl), 8=Blue (dark or electric)
6 Option Currently used for miscellaneous options.
3=Blue hands (Aqua Terra), 4=Gold hands on steel model (Aqua Terra)
7 Option 0=undeclared, 3=Foldover clasp for strap models, 9=Rubber strap
8 Option 0 or not shown=standard bracelet, 1=rubber strap with steel clasp (Pro Diver) or black alligator strap (Aqua Terra), 3=rubber strap with non-steel clasp, 7=brown alligator strap (Aqua Terra), 8=blue sharkskin strap (Pro Diver), 9=green sharkskin strap (Pro Diver)
So, a model 2831.80.08 is a full-size Seamaster Professional, stainless steel case, with blue bezel and dial, on the optional blue sharkskin strap.
http://chronocentric.com/omega/seamaster.shtml