WWI Austro-German military post: JAN 1918 registered cover from Austrian "Liquidierender Rechnungsführer der | k. u. k. Gebirgshaubitzdivision i. d. Türkei" (Paymaster of the Austrian Mountain Howitzer Division) in Palestine to War Ministry, VIENNA; marked on front by 2-line violet unit cachet; carried to Syria where dispatched using German military post in DAMASCUS, postmarked 11-1-18 at DEUTSCHE FELDPOST 372 (postmark Ba M-15) and marked by very rare registry-label "K. D. Feldpoststation 372" [Kaiserisch Deutsche field post station] Ba R-40-5. Unfranked, as military mail - handstamped "einschreiben" and "Portofreie Dienstsache" (postage-free service mail); backstamped by special cachet of Austrian "Liquidierender Rechnungsführer". Folded 1cm vertcally at right; very fine. Estimated value $4000+