What is COSC?
Contrôle Officiel Suisse des Chronomètres(COSC) is one of the main bodies that certifies the accuracy of Swiss watches. For an automatic watch to be certified as a chronometer, it has to be accurate to losing up to 4 seconds or gaining up to 6 seconds per day (-4 to +6 seconds). That's just a 10 second spread for a mechanical device. Watches are individually tested and certified on behalf of the manufacturers. You can find some of these COSC certified watches on Amazon at somewhat attainable price points. Here are some of the COSC certified watches that I found on Amazon at prices between $600 and $1700.
Certina Action DS
Certina has been making watches since 1888. In 1959, they came up with the DS concept for extreme shock resistance. That tradition continues with the current DS line.
The Certina Action DS Chronometer (Amazon photo) |
The Certina Action DS is a diver-style watch with 300 meters of water resistance. However, the manufacturer cautions that while it is suitable for swimming, but not diving or snorkeling. The watch has a 43mm diameter case that is 13.67mm thick. As of this writing, it is regularly priced at just less than $650. You can find it here on Amazon.
Tissot Heritage Automatic 1938 COSC
If you are looking for a classic vintage watch style with a very price automatic movement, the Tissot Heritage Automatic 1938 COSC might be the choice for you. It has all the style of an old school field watch and comes in several dial colors. This one is pink, but I prefer the black or white dial options.
Tissot Heritage Automatic 1938 COSC |
This Tissot has a 39mm case that is 11.1mm thick. This watch retails for less than $850. You can find it here on Amazon.
Mido Ocean Star Diver 600
If you want a real dive watch with 600 meters of water resistance and an 80 hour power reserve, the Mido Ocean Star Diver might be a good choice.
This watch has a 43.5mm diameter case that is 14.55mm thick. As of this writing, it's 30% off bringing it down to below $1300. You can find it here on Amazon.
None of these watches are cheap, but they are all tested to the highest standards of mechanical accuracy. While you do pay a premium for these watches, they are all considerably more affordable than a Rolex. To read more about the certification process, here is the COSC website.