The Sumo is in the middle of Seiko’s wide and sometimes confusing range of dive watches It costs more than the Turtle but significantly less than the Marinemaster. As an everyday tool, it s really all the watch you need. It has the automatic 6R35 movement with decent accuracy and 70 hour power.
With 200m water resistance the case seems large at 45mm but wears like a smaller watch.
This particular model is a recent limited edition in steel with a special black coating.