Identification Help

Hello,

I have inherited an old IWC and would like to find out more about the watch,
such as model/ref number, year of production etc. Would appreciate any help
you can give me. Thanks!

Inside mechanism engraving reads:
INTERNATIONAL WATCH Co SWISS
1710571
21 JEWELS
PAT. APPL. C. 854

Engravings on inside of back case:
IWC PROBUS SCAFUSIA
INTERNATIONAL WATCH Co SWISS
"174" and "18K 0.750" (Hallmarks)
R807A
1703141

Here is data from the Date Your IWC app. Wear it in good health.

Thank you for the information Bill!
Much appreciated.
/Tomas