| Brand | Seiko |
| Caliber Number | 8R28, 8R28A |
| Family | 8R |
| In-House? | Yes |
| Movement Type | Automatic, Chronograph |
| Jewels | 34 |
| Power Reserve | 45 hours |
| Vibrations Per Hour | 28,800 bph |
| Parts | 292 |
| Hacking Seconds? | Yes |
| Hand-Windable? | Yes |
| Functions | Central hours; central minutes; central chronograph seconds; small running seconds at 3:00; 30 minutes counter at 9:00; 12 hours counter at 6:00; date at 4:30 |
| Country of Manufacture | Japan |
| Known Models | Ananta SRQ011 (Add your watch to the comments below…) |
The Seiko caliber 8R28 (aka 8R28) is an in-house automatic chronograph movement with 34 jewels, a power reserve of about 45 hours, and beats at 28,800 vph. As part of the 8R family of movements, the 8R28 features a vertical clutch and column wheel chronograph system. This movement is entirely made in Japan.
Average Accuracy Rating:
What can you expect as far as timekeeping?
Seiko official documentation claims that the average accuracy of the 8R28 is between -15 to +25 seconds per day in normal operating conditions and temperatures of 5C to 35C (41F to 95F).
Examples of watches with this caliber:
The caliber 8R28 pictured was found in a Seiko Ananta model SRQ011.
Additional Resources:
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