Free diving refers to a sport that does not carry an air bottle and only regulates the breath and holds the breath to go deep diving as far as possible. Since the 1970s, this sport has only been regarded as an underwater extreme sport and has not been widely promoted to the public.
Therefore, it can make the whole dial more vivid and clear. With the timing of big seconds in the dark also provides a striking indication. With high-tech long afterglow material coating, fearless in the dark, to create for the fearless.
Drawing bottom cover
Stainless steel wire drawing tight bottom back cover, 100 meters diving, ingenious, waterproof to do better.