50 Kop. Agriculture exhibition, horizontal pair, left stamp with normal overprint, right stamp with inverted overprint \"Eesti post\", tied by cancel \"ELVA B, 14 VIII 41, perfect quality. Pairs with tete-beche of the overprint by of this issue are extremely rare. From of this stamp are only 2 examples known! Photo expertize Gerhard Krischke: \"the condition is perfect. \" and photo expertize Thomas Loebbering BPP: \"genuine and immaculate. \"