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Caliber 6L37

The thin, high-performance 6L37 movement is the result of more than 100 years of heritage and technical expertise.
The 6L37 caliber is SEIKO’s thinnest automatic mechanical movement ever. While meeting the strict SEIKO Divers standards, it is equipped with a power reserve of more than 45 hours and high precision with an accuracy rating of +15 to -10 seconds per day.

Seiko's original technology


SPRON is a proprietary Seiko alloy. Used for the mainspring and hairspring, it was developed to be resistant to breakage, corrosion, and wear. The use of this special alloy in the 6L37 caliber results in stable and long-lasting precision.


Diashock is a structure developed to enhance the movement’s resistance to shock. It is used as a bearing, such as those used for the balance wheel pivot, a section of the movement that is especially sensitive to sudden movements and jolts. With Diashock, the structure maintains high stability even when subjected to these conditions.

Caliber 6L37
Driving system:Automatic
Frequency:28,800 vibrations per hour(8 beats per second)
Precision:+15 to -10 seconds per day
Power reserve:45 hours
Number of jewels:26



Limited Edition


Limited Edition