Sweden. Military postal stationary Facit Mu2, Proof for Mu2 by Jacob Bagges Sedeltryckeri 1916 in Lithography, black on green-blue paper. Some difference in the wording on front "stab, kvarter" instead of "kvarter, stab" that's found on the issued issue. Also a large square with text that is omitted from the issued stationery. Also a very interesting type-writed note in blue "Korrektur d. 5/5 1916" (proof dated May 5, 1916). A must for postal stationery exhibit regarding the first Swedish issues of military letters free for the sender. Four Mu2 proofs are known, but only one known with notation "Korrektur". Excellent quality. Exhibition item!