Sweden. Military postal stationary Facit M12 P , Proof, full cover, for M12 issue (five known) with larger distance between the wording on front MILITÄRBREV and the frame with the posthorn to the right than the normal issue. Also there is printed on back on the reply-stamp the security pattern (same as on the inside of the envelope). This is not done on the reply-stamp on the issue. This is a very good item to be able to show the printing story of M12 issue. Excellent quality. Very rare and an exhibition item!