1917Reg and Express service letter, liberated from postage, paid only fee 30h after/behind express delivery, CDS Etappenpostamt 180/ 12.II.17, in front also on reverse straight line postmark K.u.K Fliegerersatzkompanie No.10, on reverse worse arrival postmark. Wiener Neustadt/ 13.II.17, vert. fold and fold corner, after all good condition