Now then, does anybody know what this type of cassette was/is called please.
In the 1970s I worked as an audio typist along with another girl at Green Shield Stamps in Dudley. The Representatives used to visit the companies in their various areas who used the stamps, they would then dictate into an audio machine what work they had done that day and send the tape to us to type out so that we all had a paper copy.
The tapes they used weren't any of the cassette types that were around then or today. These magnetic tapes they used were the same shape as the cardboard on the inside of a toilet roll, but larger, about 6 inches long. They were posted to us in a flat envelope and we would put them on our audio machine and use headphones to do the audio work.
I could have made it easier for myself if I'd been looking for a Dictaphone rather than an Audio 