Omega Seamaster 1957 Railmaster Limited Edition Co-Axial Watch (184.108.40.206.01.002). Caliber Omega 8806 Automatic Co-Axial Master Chronometer movement. Black dial and index hour makers. Fixed steel bezel set on a 38mm stainless steel case. Sapphire crystal on top and exhibition case back. Water resistant to 60M. Stainless steel bracelet. Limited edition to 3,557 pieces worldwide.