This nifty, unique post card from Italian-occupied Libya was unnecessarily marked postage due, and charged(?) 6-Kronen by Austrian postal authorities due to their belief that the sender had not applied any postage(it was on the front!)! It was mailed on September 2, 1921, from Tripoli, Italian Libya, to Vienna(arrived on: 9/7/21, and got a pretty good CDS!), Austria! The sender was a soldier with an Italian Army transportation unit(12 Autoparco(Motor Pool), 17 Autoreparto(Auto Detachment). It looks like the addressee was someone who was exchanging post cards with the sender. As for the overprinted("Libia"), blue, 25-Centesimi Italian issue, it's in good-very good condition! The blue, 5-Kronen, and 1-Kronen, Austrian postage due issues have some tears and/or significant perf damage. Noted imperfections aside, this post card remains a neat piece of Italian military, Italian Libyan, and Austrian postal history!