The Prospex line of professional divers from Seiko has long been a rich source of fine watches and superb engineering, sadly less known than they deserve due to Japan-only sales. This one is worth questing for though, it's the new-for-2013 SBDB008, in the Prospex Marinemaster collection. Spring Drive (cal 5R65), DLC titanium shroud, titanium nitride (the gold colored bits) highlights, date window tucked in at 4:30, and a new handset. From the sheen, it looks like the bezel insert is ceramic, which would be a nice touch. I like this one, though it's tall at 16.2mm thick. Width not known, but we know that those are 22mm lugs so probably 44mm plus. 72 hour power reserve, and that movement is rated at +-15s/month.
It's on page 41 of the Japanese-language Seiko 2013 catalog (PDF). From that, list price is 399,000JPY, or about $3,900USD as of today. Limited edition of only 300 pieces, on the bright side AZ Fine Time has announced they'll be getting these for US sale.
This is the first time Seiko has put Spring Drive into one of their Tuna series; it's a nice upgrade. Heckuva dive watch for half the price of a new Rolex, and you get one of the most famous dive watches around that looked too good to be true when the "Tuna" first came out in the 1970s.
Little note on Spring Drive as well. A Seiko executive has told us that (at least for the rest of the world outside of Japan) they will be keeping Spring Drive movements exclusively for Grand Seiko collection pieces.