Every product is carefully selected by our editors. If you buy from a link, we may earn a commission. Learn more Recently, Casio expanded the F-91W line to make the watch more of a fashion item. Back ...

The Casio F-91W is probably the most popular wristwatch ... There’s a lot of history in this classic watch. That said, there is exactly one problem with this watch: it’s barely water resistant.

[Mattia] decided that a spare key card might be good to have around, and that building it into his Casio F-91W watch would put the key as close at hand as it could be without getting an implant.

Or 1989’s Casio F-91W, renowned for its reliability, long-lasting battery, and minimalist design. Since its 1989 debut, it has become a global bestseller and an iconic item, popular among celebrities ...