Eterna Cal. 1438 was one of a family of automatic watch movements produced in the 1950's and 1960's.
ETA was one of the three firms “chosen” to develop advanced automatic watch movements by Ebauches SA, thanks in part to their history with Eterna. The chief designer at ETA, Heinrich Stamm, had created many of the company's important watch movements, and was famous for the Eterna-Matic line of watches. Stamm developed Cal. 1438 and its family for the Eterna-Matic Centennaire line.
When it was introduced, Cal. 1427U was the thinnest automatic movement on the market, measuring 4.5 mm high, despite a central rotor winding system.
The success of this movement made it the template for the Eterna 1466 and today's ETA 2892 family.
All non-date movements in this family are 4.5 mm thick; date versions measure 4.9 mm. All have 21 jewels and a power reserve of 49 hours. All operate at 18,000 A/h.
This movement family includes 11.5 ligne, 12.5 ligne, and 13 ligne variants.
The quickset date is operated by repeatedly pulling the crown.
Cal. 1438 is the most famous of a family of movements. All are automatic unless otherwise noted.
All movements use suffix “U” to signify Eterna-U shock protection. Movements with the suffix “B” lack a seconds hand.