It was with OMEGA's maritime legacy in mind that the brand launched its Planet Ocean line in 2005. The stylish OMEGA Seamaster Planet Ocean 600M Master Chronometer GMT pays homage to OMEGA's dive watch heritage. This model, with its scratch-resistant sapphire crystal, features a black ceramic dial with Arabic numerals, a date window at the 3 o'clock position and a central GMT hand. Mounted on the 43.5 mm stainless steel case is the world's first polished bi-ceramic black and white bezel. Here, the numerals and scaling are delivered in contrasting colours to separate night from day. Other features include an alveol screw-in caseback and a black leather strap with rubber lining. The OMEGA Seamaster Planet Ocean 600M Master Chronometer GMT is water resistant to 60 bar (600 metres / 2000 feet), and has a helium-escape valve. The OMEGA Master Chronometer calibre 8906 at the heart of this timepiece can be seen through the transparent caseback. To achieve Master Chronometer status, it has passed the 8 rigorous tests set by METAS (The Swiss Federal Institute of Metrology).