ETA Caliber 2551

Manufacturer	ETA
Caliber Number	2551
Movement Type	Automatic, self-winding mechanical
Lignes	7.75”’
Overall Diameter	17.5mm
Casing Diameter	17.2mm
Height	4.5mm
Jewel Count	21 jewels
Beat Rate / Frequency	21,600 bph / 3 Hz
Lift Angle	51 degrees
Power Reserve	~42 hours
Rotor Winding Direction	Bi-directional
Anti-Shock Device	Incabloc
Hand Count	3
Functions	Central hours; central minutes; central seconds; date at 3:00
Hacking Seconds?	No (unconfirmed)
Quickset Date?	Yes
Country of Manufacture	Switzerland, Swiss made
Known Models	(Add your watch to the comments below…)

The ETA caliber 2551 is a vintage ladies size automatic movement with a date.

ETA 2551 VS 2550:

There is a similar caliber 2550 with the main difference being that the 2551 has a date, whereas the 2550 is a true no-date.

ETA 2550/2551 Tech Sheets (pdf):

Known brands using this calibre as a base:

• Tissot 744

Please add more in the comments below…

Additional Resources:

• More ETA watch movements