Swiss Stamped Cover To Dachau Concentration Camp

An unusual find, looks like it is dated 21.III.45, which is shortly before the end of the war.

Anyone have any info on this ? Value ?

There is no enclosure, no return address on front or back.

Commandant at that time was Eduard Weiter. who fled the camp circa April1945 and died in a subcamp at Schloss Itter either 27 April or May 2, by self-inflicted gunshot or being murdered by another SS member.

It seems to me the sender did not know Weiter's identity or the details about Dachau and its subcamps, hence the bare address. The Swiss skincare firm Weleda had contacts with the Dachau administration.