While browsing our website, you’ve most likely come across a term called the ISO 6425 Standard. The ISO 6425 standard is set by the International Organization for Standardization, and sets minimum requirements that a diver’s watch must meet before it can be classified as such.
Water Resistance – The most predominant rule in the ISO 6425 standards is water resistance. All watches must have a water resistance of at least 100 meters, or 330 feet. Generally, diver’s watches are made with water resistance between 600 and 1000 feet.
Readability – Above all other elements of the ISO 6425 standards, a diver’s watch must be clearly readable. This includes prevalent minute markings on the face. Additionally, a watch must be readable in total darkness. This is confirmed by holding the watch about 10 inches away from the eye and seeing if it can still be read. Normally, watches pass this standard by illuminating the hands of the watch.
Notice That the Watch is Functioning – It can be difficult to tell if a watch is functioning in dark, deep oceanwater. Obviously, you’re unable to hold it to your ear to listen for a second hand. To overcome this obstacle, manufacturers generally install a well-lit second hand for clear indication of proper watch function to meet ISO 6425 standards.
Unidirectional Bezel – A bezel with minute markings of at least every 5 minutes is required on a diver’s watch that meets ISO 6425 standards. While these are fashionable markings on department store watches, these rotatable bezels allow a diver to time his or her dive and know exactly when it’s time to head back to the surface during a dive.
Chemical Resistance – Normal watches would take a beating in seawater due to the material they’re manufactured from. The chemical resistance test is simply submersing the watch in a saltwater solution that’s similar to the salt levels in oceans around the world for 24 hours. This ISO 6426 standard element tests for true rust resistance in the composite materials of the watch.
Shock Resistance – There are two tests applied by ISO 6425 standards to a watch to make sure it can withstand the force of a hefty blow when underwater. The test lays the watch on its side, while the second is an impact directly on the face of the watch. A hard plastic hammer weighing 3 kilograms is forced on the watch with a velocity of 4.43 meters per second, or nearly 10 miles per hour.