Seiko

Seiko 6R5J open heart power reserve: 72 hours

The Seiko 6R5J open heart is an automatic movement that runs for about 72 hours (about 3 days) from full.

Found in

Presage Sharp Edged Open Heart, Presage Classic Series Open Heart, SPB417, SPB469, SPB471, SPB480

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 18 hours of wear fills the Seiko 6R5J open heart. 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 72 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 Seiko 6R5J open heart: 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.