MONACO, 1925, 1fr on 50c BROWN ON ORANGE POSTAGE DUE - DOUBLE SURCHARGE - MINT NEVER HINGED, #J27a, well-centered, fresh an very fine, rare, only 150 known, signed Calves twice, with 2019 Roumet cert., cat. $750.00 as hinged, Yvert TT #17a @ €1,400.00, Maury TT #17b @ €1,850.00 (Image)