Our most nostalgic styles are boldly reimagined with fashionable elements and familiar nods to our history of firsts. 100M Waterproof: By using a h2o resistance of nearly 100M you can easily manage most predicaments in everyday life, for instance washing arms, rain, swimming(make sure you tighten the crown when likely https://www.watchesworld.com/a-history-of-watch-reference-numbers/