It is popular for its clean design without a date and the plastic crystal gives it a classic look.

This model was a hot topic as the world's first diver's watch equipped with a rotating bezel to measure diving time. It was developed for true professional divers who work in harsh environments.

There are "borderless" models, where the index luminous material has no border, and "bordered" models, where the luminous material has a border, and the different specifications depending on the era are popular among enthusiasts.