[78-L] What are these?

[David Lennick]

I found 4 green flexi discs today, about 4 inches in diameter with a square 
center hole, no markings or ID, very fine grooves, most cut on 2 sides. They 
appear to play at 33 but don't track well (very fine microgroove, I presume) 
and all I can hear is a faint male voice. Are these from a dictating machine? 
The material is similar to red Edison discs I've seen.

dl