Why is the fact critical? If a unidirectional bezel is knocked and accidentally moved over a dive, it may only Screen an extended underwater time. Meaning the wearer will overestimate instead of underestimate immersion time, As well as in circumstances that require decompression stops, this can be a make-it-or-crack-it component https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/