The Alpina 355 watch movement, produced around 1950, is a manual wind movement with a sub-second function. It features an unconventional crown mechanism with a rocker bar, and in some variations, a ratchet wheel is positioned on the back side. Different variants of this movement are known to have variations in the placement of the click on the dial side and the crown wheel which may or may not have a functional role. However, the specific assignment of these variants to the numbers 1237, 1238, 1245, 1249, and 1269 remains widely unknown, except for the AS 1245 which is confirmed to have a ratchet wheel on the back side.