Omega, Seamaster Aqua Terra Co-Axial, a stainless steel wrist watch, no. 80553005, circa 2004, automatic movement, 27 jewels, cal. 2500, adjusted to 5 positions and temperature, black dial, applied tapered baton and luminous markers, luminous arrow minute and tapered hour hands, luminous centre seconds hand, date aperture at 3 o'clock, screw down crown, screw down display back, on an unsigned brown leather strap with a pin buckle, case back, dial, movement and crown signed, accompanied by an Omega box, international warranty card, chronometer certifate card and outer card packaging, diameter 38mm Making its production debut with Omega in 1999, the Co-axial escapement was the result of 25 years independent development by George Daniels, in an effort to improve on the 250 year old lever escapement, invented by Thomas Mudge. Met with resistance by many Swiss brands, it was finally adopted by Omega and is now used widely throughout their collection.