Seiko has a rather long and storied history designing and manufacturing dive watches, used by individuals from across the spectrum of jobs – from many of us desk divers all the way to Navy SEALs.
 
And there exist numerous vintage Seiko divers popular with collectors, but few are rarer than the 1999 Seiko ScubaPro 7C46-7011 “Tuna” dive watch here, with its original strap, inner/outer Seiko Sports boxes, instructions manual, and warranty paperwork.  
 
Only 300 of these were made by Seiko to celebrate the new millennium, and these were only sold in Japan-based ScubaPro shops. 
 
Seiko first introduced their so-called 6159 “Grandfather Tuna” (you guessed it, the first Tuna – nicknamed after their distinctive shape) in 1975, and quickly followed with a number of similarly-designed divers through the 7549, and then introduced the 7C46 in 1986.  Within the 7C46 line, Seiko was intent on implementing more advanced materials on their top-grade watches – like the one here.
 
Per Fratello, "Seiko divers rank among my favorite watches of all time.  I tend to believe that Seiko has carved out a relatively unique design language for a genre that spawns multitudes of copycats.  Four-o’clock crowns, signature hands, and a penchant for simplicity are some of the traits that come to mind.  The Seiko [7C46] series that debuted in the mid-’80s is unmistakably a Seiko.  However, it’s different than anything else in the collection, and frankly, I love it!"  For an in-depth look at Seiko's Tuna divers, Fratello again has the answer, here.
 
Seiko has produced limited edition divers for Scubapro in the past, albeit seldomly.  In 1977 they took the Seiko 6306-7001 and made the 6306 Scubapro 450, produced in batches until at least till 1979.  Like the 1999 Seiko 7C46 ScubaPro here, its 6306 brethren is also a true grail watch.  
 
The ScubaPro 450 was part of a marketing agreement between Seiko and the diving firm; with that said, the changes were mostly surface in nature and limited to the signed dial and unique rubber strap.  Often faked, the ScubaPro 450 dials received a unique dial code: 700L T to 700J T, and were produced from circa 1977 through late 1978/early 1979.
 
Per ScubaPro, the company is "the world's most iconic brand of dive equipment, built by and for those whose passion is found below the water's surface. Founded in 1963 by Gustav Dalla Valle and Dick Bonin, SCUBAPRO remains the industry's gold standard for innovation, performance, reliability and durability.
 
This 1999 Seiko 7C46 ScubaPro diver comes on its rubber strap, and with nylon strap, rugged travel case, and springbar tool.