Rare early model of envelope letter with matching envelope sent by a Czech inmate from KL Sachsenhausen/Oranienburg in 1940 to his wife in Bohemia and Moravia. Inmate is called Jaroslav Fiala, and he had number 4476 and he was imprisoned in block 50B of the camp. Letter is complete and also envelope is complete even with post-stamp. Envelope has also the censorship ink stamp. Overall condition is excellent for this rare type of letter from one of the oldest concentration camps erected by the Nazis in Germany!