I didn't know the device. Also I didn't know that Kai Krause who later got famous through his Kai's Power Tools was an electronic music expert who sort of did sales for Sennheiser in 1977, according to this page (https://de.wikipedia.org/wiki/Sennheiser_VSM_201 - only on the German WP, it seems). He also wrote the manual for it.

His German WP page also claims that he sold a VSM 201 to Neil Young in 1982! https://de.wikipedia.org/wiki/Kai_Krause

English WP has less details on that part of his life, especially the VSM 201 :) https://en.wikipedia.org/wiki/Kai_Krause