3
votes
0answers
63 views

Who invented and marketed the first “clip on” headphones?

Headphone style terminology seems dodgy at best, but I'm trying to determine what company first sold this style of headphone in the US: I've seen them variously described as "on the ear," "clip on" ...
3
votes
2answers
218 views

Which technologies/commodities were available during the 30s on USA?

This is for a RPG story, so I don't need too much accuracy, but the common stuff would be very useful :) I've already found this site: http://www.paper-dragon.com/1939/ but would like more ...