Eterna manual caliber 852 S

Eterna manual caliber 852 S
There are 2 movements 852, one with central secondhand and one with a lower sub second.
This gives confusion but with a subsecond it is also caliber 852 but with a S.
Both a manual  from 1949
Case no: 2828330
Movement no: 2892582
This one is fully restored by a master watchmaker.