I just received this today...it is fairly rare and you may have never seen one of these as I have only seen one or two over the years.
Lately, I have been on a vintage Seiko diver kick. A month or so back, I purchased my first two shrouded divers (H501 and H601). This time around, I purchased a Seiko 7c43-6020 "Mini-Tuna", which are a part of Seiko’s Quartz ‘Professional’ series. Although it is called the mini-Tuna, it's still a pretty reasonable sizeand is comparablein size to many current day divers.
It wears very similar to my H558 "Arnie" and is in very good shape (especially the case) for a watch of its age. It appears to be all original and the quartz movment (7c43) is working well.The 7c43 is the predecessor of the high torque 7C46 quartz bigger brother, which was developed exclusively for the quartz tunas (both 300m and 1000m).
These began production in 1986 and, based on the serial number, it's "born date" is May '91.
Movement: Seiko 7c43 quartz - considered by some to be a HEQ
Case diameter: 44mm
Case thickness: 12mm
Crystal: Domed Hardlex
Other: 200m WR, plastic shroud, rubber strap.
A few photos that i took today...the time was wrong, but so what
And a group shot with the other watches that I have at work today...