What is the turntable on the watch for?

Diving watches generally have such a function. Diving watches usually have a rotatable dial, which can help divers easily read the elapsed diving time. The reading dial of a real diving watch can only rotate counterclockwise in one direction. If the turntable can rotate clockwise, it may cause the diver to read less time than the actual diving time, putting the diver in high danger.

You can set the time in the second time zone by turning the outer ring. Generally, when going abroad, you can know the time in the local time zone and the departure time at the same time.

Oxygen has a certain time. When diving, aim 0 at the minute hand, so it is easy to see how long you have been diving.