Why is that essential? If a unidirectional bezel is knocked and unintentionally moved on a dive, it may only Screen an extended underwater time. That means the wearer will overestimate rather than undervalue immersion time, and in circumstances that require decompression stops, this can be a make-it-or-split-it component that helps https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/