Steel Omega Speedmaster 57 3188.8.131.52.02.002. Automatic co-axial chronograph movement Calibre 9300. Silver dial with luminescent index hour markers and silver sub dials. Date window at the 6 o’clock position. Column wheel mechanism and Co-Axial escapement. Silicon balance-spring on free sprung-balance, 2 barrels mounted in series, automatic winding in both directions. Rhodium plated finish with exclusive Geneva waves in arabesque , 60 hour power reserve. Case diameter 41.5mm. Water resistant to 100 meters. See through case back. Steel Tachymetre bezel. Steel bracelet with deployment clasp. Box and papers dated February 2015. Our reference S21031.