J-38 US Military Morse Key

This morse key was designed to be used with a US Signal Corps radio/telegraph operator training set during WW2.
Earphones were connected to the TEL binding posts, and the line to the training set was connected to the LINE binding posts. Closing the switch enabled listening. Opening the switch allowed transmission.
The key was made by several manufacturers. This one was manufactured by the Lionel Corporation, toy manufacturer who took part in the WW2 industrial effort.