ETA Caliber 2840

Manufacturer	ETA
Caliber Number	2840
Movement Type	Automatic, self-winding mechanical
Lignes	11.5”’
Diameter	26mm
Casing Diameter	25.6mm
Height	4.7mm
Jewel Count	23
Beat Rate / Frequency	21,600 bph / 3 Hz
Lift Angle	50 degrees (unconfirmed)
Power Reserve	~38 hours
Rotor Style	Ball-bearing
Rotor Winding Direction	Bi-directional (reversers)
Hand-Windable?	Yes
Anti-Shock Device	Novodiac
Regulator?	None
Hand Count	3
Functions	Central hours; central minutes; central sweeping seconds
Hacking Seconds?	No
Country of Manufacture	Switzerland, Swiss made (V8)
Known Models	(Add your watch to the comments below…)

The ETA caliber 2840 is a a vintage automatic watch movement that was meant to be an economy version of the 2800 family of movements, with some similarities to the framework of the famous 2824-2.

This caliber is found exclusively in Swatch watches from the 1990s (since circa 1991), which is why official technical documentation appears to be non-existent.

You may see this calibre described as being the no-date version of the 2842, however, there are 2842 movements without a date as well.

Additional Resources:

• More ETA watch movements