The Vintage Wrist Watch Company has dated this piece to the 1940s.
The movement is signed Elgin Nat'l Watch Co, USA and it has the serial number 41,298,415 which dates it back to 1942.

The watch measures 50mm diameter excluding the winding stem and the loop. The plated case does have wear, mainly to the screw-on case back. The plastic lens is in good condition - the watch has a screw-on bezel which is a nice sign of quality.
The black dial is signed Elgin; there are some hairline cracks and some discolouration to the hands. There is a subsidiary seconds dial and an outer minute track.
The Vintage Wrist Watch Company has dated this piece to the 1940s.
Specialists in antique and vintage wrist watches and pocket watches
You can view the stock and full dealer information on the The Vintage Wrist Watch Company Profile Page