The UMF caliber 33-50 is one of older versions of the 8 3/4 ligne midsize caliber, called "Diva" or "M3". It has got no shock protection and only seven jewels, but already uses a pallet lever excapement.
It displays hour and minutes only.
The movement itself is very lean constructed and service friendly. On the dial side, almost the whole anchor wheel can be seen, just as on skeletonized movements.
As usual for UMF, this movement has got a rocking bar winding mechanism.
The later models of this movement were released as caliber 39-50.