Spring Drive is the movement I find hardest to categorize cleanly — mechanically driven but quartz-regulated, with a seconds hand that glides rather than ticks, and here it's in a hand-wound configuration rather than the more common automatic. At 38.5mm in steel with a blue dial and a black crocodile strap, this sits squarely in dress-watch proportions, and the 30m water resistance confirms that's the intent. The glide of that seconds hand is the detail that makes Spring Drive worth cataloguing on its own terms — no other technology quite replicates it, mechanical or quartz.