Hamilton

Hamilton H-21 power reserve: 60 hours

The Hamilton H-21 is an automatic movement that runs for about 60 hours (about 2.5 days) from full.

Found in

Intra-Matic Chronograph, Khaki Aviation chronographs

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 15 hours of wear fills the Hamilton H-21. Desk days charge more slowly.
• Most automatics can also be wound by the crown. If yours has stopped, a few dozen turns gets it going before you put it on.
• Off the wrist it stops about 60 hours after it was last full.
• If it does stop, don't set the date between 9pm and 3am. Here's why.

Never let it stop

Watch Winder counts down the reserve of every watch you own and reminds you before one stops. It already knows the Hamilton H-21: type your watch's name and the reserve fills itself in.

Manufacturer's published figure. Real reserve varies with the watch's age and service; check your manual.