Pictures of this Junghans Panama Nickel Watch No. 502 N are courtesy of Deutsches Uhrenmuseum Furtwangen.
Junghans/Haller catalog 1906/1908 text:
30 Hour american style keyless lever.
Shortwinder with set hands in front.
Original instruction leaflet text:
This Watch is stem wind and stem set, has been thoroughly tested and will run accurateley thirty hours.
A WATCH that costs TEN TIMES as much will keep no better time than this, if you will treat this as well. It is not a toy, but a real watch. It must be used carefully, and should not be allowed to run down.
To set the hands push in the stem and turn. In winding be sure the stem is once more well pulled out. To regulate the watch, remove the back cap; and, if it runs too fast, move the regulator slightly toward "S" if it runs too slow, move it slightly toward "F".