|Winding:||Automatic, Bi-Directional Automatic Winding|
|Diameter:||28.0 mm (12.5 ligne)|
|Hands:||Central Hour Hand, Central Minute Hand, Central Seconds Hand|
|Production: 1983 –|
ETA’s 2890 was an ultra-thin automatic watch movement and the first in the ETA 2890 family. It was introduced in 1975, as Eterna’s movement operations were folded into ETA, and removed from production in 1983. The ETA 2892-2 (with date) was the successor movement.
Closely related to the short-lived Eterna 1504, the ETA 2890 operates at 28,800 A/h, has 21 jewels, and features an automatic winding system embedded into the movement rather than attached above it. This gives it the signature 3.6 mm depth which remains the hallmark of the family to date.
The ETA 2890 and closely-related ETA 2892 (with date) measured 12.5”’ (28.0 mm) in diameter. The oscillating weight extended to the edge of this plate, effectively winding the stiff mainspring needed to drive the high-beat 28,800 A/h balance.