Why is the fact important? If a unidirectional bezel is knocked and accidentally moved on the dive, it could only Screen a longer underwater time. Which means the wearer will overestimate as opposed to underestimate immersion time, and in predicaments that require decompression stops, this can be a make-it-or-crack-it variable https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/