A watch’s energy, meanwhile, is stored in a coiled mainspring, and is released as this gradually unwinds, powering the watch’s timekeeping functions and other complications. The number of hours of energy the mainspring provides before it needs winding—or, in the case of an automatic watch, a decent wearing or a thorough shake—is known as power reserve.
We won’t go into greater detail about the science of mainsprings, because the minutiae of watch engineering are rather unsexy, technical stuff. If you’re curious to learn more, google ‘How does a mainspring work?’ and you’ll soon discover reams of reading as dry as a good martini and equally as stupefying. The important thing to know is, mechanical watches generally need powering up every couple of days—most quality mechanical watches have a power reserve of at least 42 hours. Some, however, far exceed that figure.
Panerai is known for its oversized watches, many of which boast large power reserves. The brand isn’t bashful about it, often boasting of the length of their mainsprings on watches’ dials or in their names—for instance, a few of our favourites from their current range include the Submersible 1950 3 Days Automatic Bronzo, Luminor Marina 8 Days Acciaio and the formidable Radiomir 10 Days GMT Platinum. Panerai also produces pocket watches in white and pink gold with three-day reserves, should you be looking to put more power in your palm.