The Seiko skx175 is Seiko's two tone version of its divers watch. It is a stainless steel cased automatic utilizint the 7s26 automatic movement, presenting on a stainless steel bracelet with diver's flip clasp. It is distinguished from other seikos, such as the 173, by its dark blue dial and red and blue bezel. Production began on this watch in 1996. According to the Seiko Production Calendar [link coming!] web page, this 175 was born in October 2003.
UNDER THE HOOD: The heart of any watch is its movement. A watch, after all, is a mechanical device, and is only as good as the mechanism that drives it.
The SKX175 uses Seiko's 7s26 automatic movement, a 21 jewel mechanism produced in Singapore. [The 7s26 Picture shown below is by Keaton, with permission]
The 7s26 movement is used in all the variants of this line, including the skxa35, the skx175, and the skx007. The day/date functions are quickset, but the movement cannot be manually wound. If it is not running, the watch is started by swinging it gently from side to side. The 7s26 does not "hack" -- that is, the second hand does not stop when the crown is pulled out for setting the time. However, by turning the crown slightly backwards, it is possible to acheive a similar effect while setting the watch.
CASE: The watch is contained in a 0029 stainless steel case. This is the same case used on the skx173 and 007 variations, as well as the a35. The screw-down back is imprinted with the now famous Seiko Wave logo, and contains three numbers: The movement number [7s26] the case number  and the watch's own serial number. Seiko has been consistant in this regard; they mark today's dive watches the same way they marked the 1970's Seiko 5 automatics, making it easy to date the style and year of yesterday's watch today -- or today's watch, tomorrow.
The 0029 case is 41mm diameter, 13mm thick.
The crown at the 4 o'clock position is finely grooved and steps down slightly to the flat end; the end of the crown, like the sides and back of the case, is polished. The case top [visible part of which consists mainly of the tops of the lugs] is a brushed finish. The crown screws down firmly and is protected by an effective and aestheticly pleasing crown-guard, although this makes it somewhat difficult to tighten it fully for those with large fingers. The bezel is unidirectional with numbers in ten minute increments, dots for minute positions and line indices for 5 minute intervals. the "60" position is marked with an inverted arrow framing a luminous dot. Bezel insert is two tone, red and blue, with the red going from the "6" dot up through the "2" minute marker. This is accomplished with a neat touch; the red and blue meet in between the 2 and the 0 of the "20". All bezel markings are steel colored. The edges of the bezel are double knurled and it is slightly narrower at the top then the base. It provides an excellent grip and is well constructed, with no looseness in fit. Indices line up perfectly.
CRYSTAL: Flat Hardlex.
BAND: Stainless bracelet, with solid links and signed "Seiko" fliplock clasp.
This bracelet with half-round solid links is brushed on the surface, with a polished center and sides. Underside has a dulled finish and the fit is great.
FACE: The face of the 175 is where the differences begin. Markings are identical in placement to the 173, but the "SEIKO AUTOMATIC" below the "12" is in white rather than silver, and the "DIVER'S 200m" above the "6" is in orange, as opposed to the 173's red. The Hour and minute hands seem the same, but the second hand is a departure. It has the lume on the back or short end, and from there to the center it is black; the front, longer half of the second hand is white. This makes for excellent visibility of both ends of the second hand, and though I was initially unsure of how I'd react to it, the backwards lume actually makes it easier to see in the dark, whereas the 173's tip-of-the-second hand lume dot could blend in with the indices at the edge of the dial.
The luminous hour indices are all rounded, with circles or dots except for "3", "6", "9" and "12". "12" is a solid arrow, wider and with rounded edges. "6" and "9" are marked by elongatated circles. "3" has the day/date display.
It is a detail, but still worth noting, that the SKX175 does not contain any lume at the "3" position. In comparison, the SKX173 has a luminous marker on the outside edge of the dial, next to the day/date window -- albeit a much narrower marker than on the opposite side, at the "9". Thus when veiwed in darkness, the "3" slot on the 175 is completely blank, wereas the 173 has a clearly visible "3" marker due to it's placement of that extra sliver of lume.
Compare the two: 175 has rounded indices, orange "DIVER'S 200m", and two-color bezel...
The 175's rounded indices actually have greater surface area (i.e., they are bigger) than the square indices of the 173 and a35 model divers.
This makes them easier to see at a glance, just as the reversed lume on the back end of the second hand makes it easier to see quickly. The face doesn't seem as plain as the 173, due to the larger, rounded indices, but the overall effect works. I can't say if I'd like it on a black-bezeled watch, however. The blue and red bezel is as much a Seiko tradition as the traditional black one, both go back many years, and the black bezeled watches that I've really liked have mostly had smaller, squared indices. The 175 isn't gaudy, but it doesn't have that almost military, utilitarian purpose, either, that is had by, say, the 173 or its forebearers. It says quite clearly: "I am for diving", but it doesn't have quite the same visual connotations as a black dial/squared indice watch. It is a little more in-yer-face. Yet, recalling the vintage 150m's and other older red and blue bezeled watches, perhaps being in-yer-face is part of the Seiko tradition -- a tradition of watches built to take the knocks.
If you ever wanted to where a Jeep on yer wrist, this is the watch for you. Sure, it isn't a Hummer -- that would be the Marathon SAR or Seiko Black Monster. But the 175 is one great watch for the buck. And anyone who has seen pictures of older Seiko red and blue divers -- whether in 150m or 200m versions -- can appreciate the 175. It is a watch to last, at a price that can't be beat.