It lasts the same 1 or 3 seconds that you set for backlight, just activates when you bring your wrist upwards.
It also senses if bright out and only turns on in the dark.
Hardly anyone dives with a dive watch anymore, a tiny percentage have ever submerged in water, let alone Into the ocean. I salute those who do. There are some great pictures on here of dive watches in their natural habitat.
The water resistance and timing bezel make dive watches in particular great for everyday use.
A timing bezel is my most used feature on a watch. Mine time anything from cooking, car trips, breaks, lunch breaks, walking the dog, to how long he's been in his cage while we go out ect.
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