The Zeltbahn M31 was design to be use by the soldier as a 1/4 shelter or as a poncho. Many pictures exists of soldiers using it for camouflage purposes or to create helmet cover for example. This equipment was reversible with one side darker than the other.
The exemplar we have here is in near mint condition. It is stamped "N" on the collar. One button is missing, no tear or holes.