Seiko · 6R series
6R55
A modern Seiko date automatic with a three-day reserve, used in the Prospex 1965 Heritage Diver range.
At a glance
- Type
- Automatic mechanical
- Display / complication
- Date
- Architecture
- Three-day automatic, SPRON springs and Diashock
- Timebase
- 21,600 vph / 3 Hz
- Power reserve
- Approx. 72 h
- Jewels
- 24
Reference sources reviewed 7 November 2026. Published specifications, not independent measurements. Versions and complete-watch specifications can differ; fields without a verified figure are omitted or identified.
Find it in a watch
Seiko Prospex SPB453
An example from the linked references. Check the exact model and production generation.
What distinguishes it
Look beyond the reference.
The three-day reserve is the headline, but Seiko also highlights its spring alloy and shock-protection system. Together they show the material and construction choices behind an ordinary-looking time-and-date display.
For the enthusiast
The SPB453 is one manufacturer-listed example. Movement reserve and the completed watch’s water resistance describe different things; a calibre name does not establish a watch’s suitability for diving.