1941 Sponser - Looking at the thread for the other 41 sponser and looking at both dials, IMHO the other one has not had a dial swap as commented in the thread, both dials are identical. This one has had a service but needs a new crystal. And if I'm not mistaken this one has the factory fresh (lol) bracelet. They also talked about an ad in the other thread but I didn't find it.
Movement Date Code
Movement Serial No.
Case Serial No.
21mm x 17.5mm flat both ways on bottom and curved top to bottom on top