It also says “The device was also used during criminal investigations, for example for tapping phone lines and for recording interrogations, or for covertly recording an important conversation in a room. During the Cold War, it was also used by the former DDR (East-Germany). Below are some examples of its use.”, so this machine has an interesting history.
“While stock lasts”.
https://www.cryptomuseum.com/covert/rec/uher/report/index.ht...: “The first model of the 4000-range was introduced in 1961 and the machine was in production in various incarnations until 1966”
It also says “The device was also used during criminal investigations, for example for tapping phone lines and for recording interrogations, or for covertly recording an important conversation in a room. During the Cold War, it was also used by the former DDR (East-Germany). Below are some examples of its use.”, so this machine has an interesting history.
https://www.radiomuseum.org/m/uher_d_en_2~model.html mentions ¿some/all? of those variants.