Sweden. Military postal stationary Facit M3v8 , 1939, Blindprinted cover both front and back. Type I according to the imprint on the cutting-edges for the reply stamp. Gummed reply-stamp and set-off (spegeltryck) on back of reply-stamp on nice mounted page with full of knowledge. This is the only known type I cover according to the handbook Svensk Frimärks-Fakta 15:1. Six known blindprinted M3 reply-stamps in total, but fewer covers. Very good quality. Exhibition item!