Why is usually that critical? If a unidirectional bezel is knocked and accidentally moved over a dive, it may only Exhibit an extended underwater time. Which means the wearer will overestimate rather then underestimate immersion time, As well as in cases that involve decompression stops, this can be a make-it-or-crack-it https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/