Mechanical watches are wound by hand. A main spring is wound through the crown to store energy and then unwound gradually. The unwinding of the spring drives the hands to show the time.
The spring will need to be wound regularly, normally once every day or two.
Mechanical watches will generally lose or gain up to 30 seconds a day depending on how they are worn. This makes them less accurate than quartz watches and about as accurate as automatic watches.
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