the keyless works ...
... before patek invented this clutch mechanism in the mid-1800's that enabled us to use the crown for both winding the watch and setting the time, people literally had to wind their watch with a seperate 'key' to be inserted into the case.
naturally, getting rid of this inconvenience boosted the popularity and practicality of watches, and the significance of the invention can be measured by the fact that in a jiffy practically every manufacturer abandoned the key-winding and switched over to the keyles works construction overnight.
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