Estland (Estonia) - Elwa. 1941, black handstamped overprint ''Eesti Post'' on 3k light blue, imperforated block of four, two top stamps without overprint, cancelled at the bottom with ''Elva. Eesti'' ds, VF and scarce multiple, expertized by V. Nemvalz, Mi #3F, C.v. €3,000 for two pairs with and without overprint, Est. $750-$1,000 (Image)