The selfwinding caliber AS 1654 is with a diameter of only seven lignes, which equals less that 16mm, one of the smallest selfwindig movements ever made. It was launched round 1960 and is similar to the AS 1635, but with an increased beat rate.
As you can easily see, the small diameter requires some compromises, the maybe most noteable one is, that the hairspring length cannot be regulated when the selfwindig mechanism is mounted. But removing it is not a real challenge for an experienced watchmaker.
Due to the small diameter, it was required to build highly, which means, that the directly driven center second hand and the minute hand, which is also directly driven, like on classic movements, are located on top of each other. This classy way of construction leads to a thick movement, especially, since the selfwindig plates mounted on top add quite a large amount of height to it. Since the movement looks a bit dull, the case designers had to work and ensure, that the big height was somehow hidden on small watches.
A speciality of the AS 1654 is the extremely tiny screw balance, which is secured by two Incablock shock protection bearings. The balance doesn't beat with slow 18000 A/h, but already with top modern 21600 A/h, six "ticks" per second. This was a huge improvement for the accurancy, since these tiny movements were prone not to be ultimately precise.
How rare that combination of 21600 A/h and a balance with screws is, can be seen on the fact, that it it hardly used anywhere. The only other watch in my collection with that combination is the sligtly larger Zaria 1800.
The AS 1654 winds with two click wheel changers in both directions. These changers also decouple the rotor while manually winding the movement. Unlike similar ETA movements, the hand winding is very smooth.
On the dial side, you find the familiar construction with yoke winding system and display gears, just like it was used several decades.
There's a small oddity: The mainspring barrel is beared in a jewel, which isn't neccessiary, and additionally, the bearings of the escapement wheel and the escapement lever contain cap jewels. This is really odd, since normally, cap jewels are only used on the movement side, where they are visible, and additionally, this is the only movement, I have ever seen, where the escapement lever uses a cap jewel.
Even more strange is, that these methods to increase the jewel count aren't mentioned anywhere. Neither on the movement, nor on the rotor nor on the dial can you find the number of jewels. That's really unusual for a time, where every extra jewel added to the value of a watch.