This is the watch that started it all for me. I bought this watch new in 1979
when I was still diving, for $180 if I remember. The case is 44mm across
and 14mm thick. This is a really large watch, even by today’s standards, so
you can imagine how big it looked back in the ‘70s when the de rigeur Rolex
Submariner measured “only” 40mm x 12mm.

Although not officially issued by the military, the 6309 was available at PXs
throughout the world. Its reputation for ruggedness and affordable price
made the 6309 a popular choice for use as a service watch by many GIs.

I wore this watch almost daily for a number of years. I can't remember how
many straps I've worn out and replaced, yet after all this time it still runs and
keeps reasonable time without ever being serviced. It’s a real testament to
the quality of Seiko’s dive watches.
Seiko 6309-7049

Case Diameter: 44 mm
Case Height: 14 mm
Case length: 46 mm
Lug Width: 22 mm
Movement: Seiko 6309 17
jewel non-hacking automatic
21,600 bph
Case material: Stainless
steel
Crown: Screw down.
Bezel: Bi-directional,
indexed w/ 60 clicks
Water resistance: 150m
Vintage: 1978

Additional photos of another
6309-7049
Without question one of the most popular dive watches ever, it has been more than two decades since Seiko last  
produced the 6309 diver, yet it still inspires legions of enthusiasts. It's robust construction and large production
numbers make them readily available still today, in fact a large aftermarket has developed to support the restoration
and modification of these watches. Quality reproduction components like dials, hands crystals and bezel inserts are
available to make these old watches look new again. Seiko purists (yes there are Seiko purists) might hesitate, but
a nicely restored, serviced and accurately timed 6309 can be had for well under $200. The watch pictured above
has been restored with a number of aftermarket components, and runs at +3 sec/day.