Omega Seamaster Railmaster Co-Axial Master Chronometer Mens Watch (220.12.40.20.06.001). Caliber 8806 Co-Axial Master Chronometer automatic movement with a 55 hours power reserve. Grey dial with recessed index hour markers filled with 'vintage' SuperLumiNova. Fixed steel bezel set on a 40mm stainless steel case. Sapphire crystal on top and exhibition case back. Water resistant to 150M. Brown leather NATO strap with a NAIAD Lock design that keeps the wording upright. Omega Seamaster Railmaster Co-Axial Master Chronometer Mens Watch (220.12.40.20.06.001)