Like all of the other information, the main camps were encoded as a number: 01 Auschwitz, 02 Buchenwald, 03 Dachau, 04 Flossenbürg, 05 Gross-Rosen, 06 Bergen-Belsen (probably incorrectly marked on some cards for prisoners as Herzogenbusch concentration camp/Kamp Vught), 07 Mauthausen, 08 Natzweiler, 09 Neuengamme, 10 Ravensbrück, 11 Sachsenhausen and 12 Stutthof. Three-digit numbers from 001 to 012 were sometimes used here instead, but they mean the same thing.