The so-called “Unitas” movement family is a series of hand-winding watch movements designed for slim pocket watches. These are the last remaining classic pocket watch movements to be widely used today. Although considered “over-sized” among modern wristwatch movements at 16.5 ligne (36.60 mm diameter), they were originally considered quite compact and ultra-thin among pocket watches.
These movements are typically among the first used for teaching at watchmaking schools. Many young watchmakers have based their projects on the 6498 ebauche. They are also commonly used for skeletonizing and other artistic crafts.
The basic design of this movement dates to about 1950, when A. Reymond SA (ARSA) of Tramelan developed a new, robust, and thin yet inexpensive movement for smaller pocket watches using their Unitas brand name. The design was a traditional one used by many watchmakers, but ARSA was able to put it into mass production using more modern tools and components. It survived the consolidation of the 1960s and 1970s, absorbed into ETA and the Swatch Group in the 1980s, and remained in production until today.
| Calibre | Start Year | End Year | Jewels | Diameter (mm) | Height (mm) | Complications |
|---|---|---|---|---|---|---|
| ETA 6497-1 | 1967 | Current | 17 | 36.60 | 4.50 | |
| ETA 6497-2 | 2005 | Current | 17 | 36.60 | 4.50 | |
| ETA 6498-1 | 1967 | Current | 17 | 36.60 | 4.50 | |
| ETA 6498-2 | 2005 | Current | 17 | 36.60 | 4.50 | |
| L97 | 17 | |||||
| L98 | 17 | |||||
| Sinn SZ04 | 2006 | 2024 | 17 | 36.60 | 4.50 | Hacking Seconds, Regulator |
