Danzig, 1921 registered airmail cover from Danzig to Rudolstadt, Germany, franked by Scott # C4-6 tied by Danzig Luftpoststempel, dated June 3 1921.
 
Back of cover has Berlin Lutfpost CDS dated June 4, 1921 and Rudolstadt arrival cancel dated June 5, 1921.
 
Good condition. Michel catalog for mixed franking is around 60 Euros.