50 Heller on 25 Heller with double thinly overprint, horizontal strip of three showing a double impression on all stamps, the middle stamp unused, the two of them exterior perfectly mint never hinged, unsigned, photo expertize Brunel VP (2022) "the condition is perfect. the stamps with double overprint are very rare. ", the unused stamp by Michel not listed, the two of them mint never hinged Michel 1800.-