The case and bracelet of the Omega watch Seamaster Planet Ocean Co-Axial Chronograph Ladies' 600M watch are both crafted from 316L steel.  As suits the sporting nature of the watch, the surface finishing is predominantly brushed, with subtle elegant contrasts provided by polished elements on the angled lug sections, and the sides of the bracelet.  The deployant clasp features a concealed diving extension for wetsuit fitting, and is engraved with the  Omega watch signature and the Planet Ocean designation; it releases precisely with simultaneous pressure on both of the lateral push-buttons.  Turning the knurled rotating bezel--which ratchets in the counter-clockwise direction only for safety during dives--is a handy feature not only essential for timing dive intervals, but useful in less specialized day to day situations.  The same can be said for the highly legible black dial with its bold luminous hour indications, discreet date display, and clearly laid-out chronograph registers.  Large arrow-tipped hands with white Superluminova material also glow brilliantly, never making the owner second guess what time it is, either below the waves or on dimly lit city streets.  
The deep-diving water resistance of the Omega watch Planet Ocean Chronograph 600M watch is attained through very precise manufacturing tolerances.  A particularly robust screw-down caseback, a thick convex sapphire crystal, and a screw-down winding crown keep moisture's harmful reach away from the movement, even at the tremendous pressures exerted 2,000 feet below the sea.  Familiar from other modern  Omega watch dive watches is the screw-down helium release valve at the 10 o'clock position.  This device, useful to specialized deep-sea divers, allows the safe venting of helium-based gas mixtures that invariably accumulate inside the case.  Such gases expand inside the case and movement as the diver surfaces.  Without a mechanism to allow their egress, these gases can render the watch inoperable--an unacceptable situation during moments when an accurate timekeeper can mean the difference between life or death.    
Omega watch offers two appealing variations of its Seamaster Planet Ocean Co-Axial Chronograph Ladies' 600M watch. The first shows off the classical sobriety expected of a divers watch, with a black and silver anodized aluminum insert on the steel rotating bezel.  Its slightly more flamboyant relative is fitted with an orange anodized bezel insert.  On both models, subtle dial details and the rings around the chronograph pushers echo the color schemes of the bezel.