A dive watch is a timepiece that has been specifically developed to withstand great pressure underwater. As such, these watches often carries water-resistance over 100m / 10 ATM. The modern concept of a dive watch is born in the mid-1950s, with the introduction of the Blancpain Fifty Fathoms and the Rolex Submariner.
Following these early models, an international standard has been created, the ISO 6425 norm, which sets the rules for a watch officially named dive watch. This includes standards on water/pressure resistance, the presence of a unidirectional bezel with 5-minute markings, readability in total darkness, the presence of an indication that the watch is running in the dark (often a luminous seconds hand), magnetic and shock resistance and more.