One of my favorite watches is my Orange Bullet, a Diver’s watch. What does it mean to have Diver’s indicated on your watch: You have to meet ISO 6425 standards:
- 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 clearly distinguishable minute markings on the watch face.
- Adequate readability/visibility at 25 cm (9.84 in) in total darkness.
- 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 the magnetic field.
- 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. This test water solution has a salinity comparable to normal seawater.
- 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.
When you add it all up, you really need a tough watch. I didn’t know about the shock and magnetic resistance. I now have even more respect for my Diver’s watch. These are all very tough standards that most watches would roll over and die if they were subjected to these conditions. I guess it really matters if your life depends on it. And I thought the cool second hand markers was just for show, it is a real standard. By the way, 200N is 45Pounds!
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