Bulgars in of the Armed Forces: 1941, franked letter from Swinem++nde 18.7. With senders note in Bulgarian and German with army postal service number "M 31594" ( = 3. Torpedo boat nifty. T 13) with OKW-censorship to Bulgaria, reverse additional with address of the Bulgarian military attache in Berlin, sender adress was a Lieutenant at sea, cover with stronger aging and margin defects, in this combination but very rare!