Helvetia WW2 German Watch General Watch Co. 
This is a Helvetia 800D Watch although issued to German Armed Forces it was popular with German Intelligence officers. This particular watch does not appear to have been issued, but then we don't think the back plate is original so we can't tell for sure.
 
The case has seen better days, plate loss, pitting and scratches are noticeable on the sides of the case, the front and back are relatively unscathed.The dial is in reasonable condition, numerals are clearly visible.