ISO 6425:2018 covers divers’ watches and saturation divers’ watches. ISO 6425:2018 — scope
Its official scope specifies depths of at least 100 m and a secured diving-time measuring system visible in darkness. ISO 6425:2018 — scope
It also addresses applicable marking.
Diver styling or a ‘200 m’ rating alone does not demonstrate conformity. ISO 6425:2018 — scope
The public abstract does not confirm here the reading distance, test percentages, graduations or individual-testing procedures.
According to Blancpain, it delivered a watch to the French team for testing in 1953; this does not mean general adoption that year. Blancpain — Fifty Fathoms history
Follow the exact reference’s manual and have its condition checked; this article is not diving-safety guidance.
Frequently asked questions
Are all "200 m" watches diver's watches?
Diver styling or a ‘200 m’ rating alone does not demonstrate conformity. ISO 6425:2018 — scope
Does the standard prescribe a particular bezel construction?
The accessible scope requires a secured diving-time measuring system, but does not establish a particular bezel construction here. ISO 6425:2018 — scope
Should a dive watch's water resistance be checked?
Seiko recommends regular checks; follow the manual for your reference. A check is not a permanent guarantee. Seiko — care