I think Dan is referring to the ROW mark on the movement as the US Import Mark and the numbers in the hammerhead stamp as the case maker's mark.
If this is number 126 then, according to one of the reference websites, it is for Humbert and Co. as Dan has stated, but I'm not sure what the middle number is.
Whatever the number is, the hammerhead or hammer without a handle mark indicates that the case was made in Switzerland, but outside of Geneva.
So it looks to be a Swiss made case fitted with a movement designated for sale in the United States, indicating that it was imported into the US as a complete Swiss made watch rather than a Swiss movement fitted into a locally made case (as was often done to reduce the import taxes).
Reference material for maker's marks:
https://www.vintagewatchstraps.com/swisspdm.php