Used by signal members in fortresses, so-called "Festungsnachrichtennetz". Both earpads are "Ffh. 39 d" (Festungsfernhörer 39 doppelt) marked and "54" (ohm) marked as well as "44" dated. The metal headband comes with the original leather cover. "Dfh.b" (Doppelfernhörer) marked. It is a general headband of the Wehrmacht signal forces. Including the original cable with plug. Not easy to find! 

The "Ffh. 39 d" is absolutely identical in construction to the "Dfh.b", but it has 54 ohms per headphone.