The Omega Seamaster Railmaster Co-Axial Master Chronometer 40 mm (Ref.
220.10.40.20.03.001) is a timepiece that seamlessly blends Omega's rich heritage with
contemporary watchmaking advancements.
 
Below are its detailed specifications:

Case:
Diameter: 40 mm
Thickness: Approximately 12.5 mm
Lug-to-Lug: 46.5 mm
Material: Stainless steel
Water Resistance: 150 meters (500 feet)
Case Back: Oriented caseback featuring a NAIAD LOCK design to keep the wording in
position
Crystal: Scratch-resistant sapphire crystal with anti-reflective coating
 
Dial:
Color: Vertically brushed "blue jeans"
Indexes: Recessed hour markers filled with light grey Super-LumiNova
Hands: Brushed stainless steel hands filled with light grey Super-LumiNova
Features: Beige central seconds hand and transferred "Railmaster" indication
 
Movement:
Caliber: OMEGA Co-Axial Master Chronometer Calibre 8806
Type: Self-winding movement with Co-Axial escapement
Power Reserve: 55 hours
Features: Resistant to magnetic fields reaching 15,000 gauss; free sprung-balance with silicon balance spring; automatic winding in both directions
 
Bracelet:
Material: Stainless steel
Lug Width: 20 mm
Clasp: Fold-over clasp with push-button release
This model pays homage to the original 1957 Railmaster, which was designed for
railway staff and others working close to electrical fields, offering superior anti-magnetic properties.