Why is the fact important? If a unidirectional bezel is knocked and unintentionally moved on a dive, it may only Show a longer underwater time. That means the wearer will overestimate instead of underestimate immersion time, As well as in circumstances that involve decompression stops, this can be a make-it-or-break-it https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/