Sweden. Military postal stationary Facit Mu1, Proof for Mu1 by Jacob Bagges Sedeltryckeri 1916 in lithography, black on grey-yellow paper. Some difference in the wording on back "stab, kvarter" instead of "kvarter, stab" that on the issued stationery. The perfect start for a postal stationery exhibit regarding the first Swedish issues of military letters free for the sender. Extremely few Mu1 proofs are known. Excellent quality. Exhibition item!