Complication
Power Reserve Indicator
A fuel gauge for the mainspring.
What it does
Shows how much stored energy remains before the watch stops, usually as a small arc-and-hand gauge. It's most useful on hand-wound and less-worn automatics, telling you when a wind is due.
How to read it
Full means recently wound (e.g. 70 hours); as the mainspring unwinds the hand falls toward empty. Wind (or wear) before it hits zero to keep good timekeeping.
Impact on value
Slightly positive; a practical and elegant addition, common on Grand Seiko and haute pieces.
Keep reading
- Complication
Perpetual Calendar
Knows the date, month, and leap years — until 2100.
- Complication
Tourbillon
A rotating cage that averages out gravity's error.
- Complication
World Time
All 24 time zones readable at once.
- Complication
Annual Calendar
Knows every month length except February.
- Complication
Alarm
A mechanical buzzer on your wrist.
- Complication
Minute Repeater
Chimes the time on demand, to the minute.