unused Block Larger Than four 10c Parcel Post Due (JQ4), B. plate no. 6250 block of six, immense full selvage, four stamps never hinged, extensive separations in selvage (as usual) which are hinge reinforced, also small selvage thin spot, otherwise fine appearance, a very nice appearing spacefiller for one of the rarest and most challenging U.S. 20th Century plate no. blocks, Scott retail $10,500.00 photo