Omega Caliber 8605

Brand	Omega
Caliber Number	8605
Movement Type	Automatic, Chronograph
Power Reserve	60 hours
Vibrations Per Hour	28,800bph
Hairspring	Silicon Si14
Shock System	Nivachoc
Features	Co-Axial Escapement, date, GMT hand
Country of Manufacture	Switzerland
Known Models	Planet Ocean GMT

From the Omega site:

Self-winding movement with Co-Axial Escapement for greater precision, stability and durability. GMT with time zone function. Silicon balance-spring on free sprung-balance, 2 barrels mounted in series, automatic winding in both directions to reduce winding time. Rhodium-plated balance bridge and oscillating mass, luxury finish with exclusive Geneva waves in arabesque.