Man, I've got a treat right from the 80's today.
This is (Head) Telephone Dynamic Stereophonic aka TDS-6. Came in all kinds of colors, and I wish I'd have blue, but I might just try and repaint the shell one day. Though even yellow looks quite gorgeous.
Mine have 6.35mm jack as the connector though, for whatever reason. Not sure if they came from factory with that, maybe the wire has been replaced at some point.
Other than that, they are working very nicely and the sound... Ah, well, can't say nothing about the sound. I haven't had time to compare them to my current headphones right now, but if they will be good, they will replace my current PC headphones which I use to clean up pops and clicks from vinyl records.
If they are not that good, they will replace my on-the-go headphones, which I use just to listen to the music. They are definitely good enough for that.
Also, point of interest: soviet word for this item was actually closer to the english one than the current word used in russian. Head telephone is pretty much literally headphones, while current russian word is something akin to "on-the-ear-ers" if I were to translate it. Never knew it!