| Manufacturer | ETA |
| Caliber Number | 2851 |
| Base Caliber | ETA 2850 |
| Family | ETA 2800 series “Gabarit” |
| Movement Type | Mechanical, manual-wind |
| Lignes | 11.5”’ |
| Diameter | 25.6mm |
| Height | 4.3mm |
| Jewel Count | Varies |
| Beat Rate | 21,600 vph, 3 Hz |
| Lift Angle | 52 degrees |
| Power Reserve | ~38 hours |
| Hand-Windable? | Yes |
| Anti-Shock Device | Incabloc |
| Hand Count | 3 |
| Hand Sizes | 1.5mm / .90mm / .25mm |
| Functions | Central hours; central minutes; central sweeping seconds |
| Hacking Seconds? | Yes |
| Country of Manufacture | Switzerland, Swiss made |
| Known Models | (Add your watch to the comments below…) |
The ETA caliber 2851 is a vintage time-only manual-wind mechanical movement. It is a true no-date movement.
This caliber is an early member of the ETA 28XX family of movements (Gabarit).
Documentation for this caliber was found as far back as 1976.
2851 VS 2850:
The ETA calibre 2851 is basically a lower beat rate version of the cal. 2850. The 2850 beats at 28,800 vph (4 Hz) and the 2851 has a frequency of 21,600 vph (3Hz).
Additional Resources:
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