ISO 6425:2018 specifies requirements and test methods for divers’ watches and for saturation divers’watches for use in deep diving (see Annex A which deals with watches for saturation diving).
It applies to divers’ watches designed to withstand diving in water at depths of at least 100 m and equipped with a secured measuring system to indicate the diving time, which is visible in darkness.
Moreover, it indicates the marking which the manufacturer is authorized to apply to them.