Deepstar

The Aquastar Deepstar makes its point with an oversized chronograph counter at three o’clock and a bezel that looks unlike the usual dive-watch fare. Introduced in 1965, it paired a diver’s watch with a stopwatch and a system for calculating repetitive dives—an unusually specific brief that gave it an equally specific face.

For that original combination, choose the chronograph rather than the Deepstar II, which translates the design into a smaller, time-only watch with small seconds. The modern chronograph returned in 2020 with a 40.5mm case; the subsequent 39mm version is worth seeking if you want proportions closer to the vintage watch without taking on a vintage movement. Neither wears quite like a slim skin diver, so case thickness matters as much as diameter here. Those distinctive bezel markings deserve attention, too: they belong to the Deepstar’s historical dive-calculation system, not a conventional elapsed-minute scale.