ISO 6425 standard for diving watches

The standards and features for a dive watch is regulated by the ISO 6425 standard. Besides the dive watch being water resistance to a minimum of 100 meter depth rating, the ISO 6425 also provides a minimum requirement for a mechanical diver's watches, take note that a quartz and digital watches have slightly differing readability requirements such as:

• Strap/band solidity. This is tested by applying a force of 200 N to each springbar (or attaching point) in opposite directions with no damage to the watch of attachment point.
• The presence of an End Of Life (EOL) indicator on battery powered watches.
• The presence of a unidirectional bezel with at least at every 5 minutes elapsed minute markings and a pre-select marker to mark a specific minute marking.
• The presence of an indication that the watch is running in total darkness. This is usually indicated by a running second hand with a luminous tip or tail.
• Magnetic resistance. This is tested by 3 expositions to a direct current magnetic field of 4,800 A/m. The watch must keeps its accuracy to +/- 30 seconds/day as measured before the test despite having the magnetic field.
• The presence of clearly distinguishable minute markings on the watch face.
• Adequate readability/visibility the watch should be read from a distance of 25 cm (9.84 in) in total darkness.
• Shock resistance. This is tested by two shocks (one on the 9 o'clock side, and one to the crystal and perpendicular to the face). The shock is usually delivered by a hard plastic hammer mounted as a pendulum, so as to deliver a measured amount of energy, specifically, a 3 kg hammer with an impact velocity of 4.43 m/sec. The change in rate allowed is +/- 60 seconds/day.
• Chemical resistance. This is tested by immersion in a 30 g/l NaCl solution for 24 hours to test its rust resistance. The testing water has a salinity of ocean salt water.