1892-96, Elephant, 4c green and black, bottom sheet margin single with inverted center, full OG, previously hinged, VF and strongly undervalued, C.v. $225 (Image)

Air Post stamps and covers. 1936, Palm Trees, black surcharges ''six cents'' on 2c violet, 3c brown and on ''Official'' 1c green, complete set of three, very fresh, unused, no gum, VF, A. Fiecchi certificate, C.v. $750 (Image)

Air Post stamps and covers. 1936, Palm Tree, surcharged issue, complete set of three used on addressed FDC, cancelled ''Monrovia. 18.11.1936'', minor perforation soiling, still VF and scarce, C.v. $825 for used stamps off cover (Image)

Air Post stamps and covers. 1941, Three-Motor Airplane, inverted black surcharge 50c on 2c red orange, full OG, LH, VF and scarce, J. Stolow guarantee hs, C.v. $225 (Image)

Air Post stamps and covers. 1941, Seaplane, inverted black overprint on $1 blue, right sheet margin single, full OG, very light trace of hinge, VF, expertized by A. Diena, Stolow guarantee hs (Image)

Air Post stamps and covers. FIRST FLIGHT COVER: 1943, First Flight Liberia - USA, surcharges with obliteration of ''1941'', complete set of ten used on registered flown cover from Monrovia to New York, address is faded, all appropriate markings and arrival ds, mostly VF (Image)

Official stamps. 1894, Hippopotamus, red overprint ''O S'' on $1 ultra and black, complete sheet of ten (2x5), full OG, NH (middle stamps) or hinged, VF, C.v. $275 as hinged singles (Image)

Official stamps. 1894, Hippopotamus, red overprint in capital letters ''O S'' on $1 ultra and black, this overprint in green or black had been used for $2 and $5 stamps only, full OG, LH, VF and scarce, L. Miro expert’s hs on reverse (Image)