1928, Colombia issue 'SERVICIO DE TRANSPORTES AEREOS EN COLOMBIA' 10c. blue-green with red opt. 'ECUADOR / PROVISIONAL / 50 Cts. 50' block of four from lower margin, mint never hinged with typical uneven gum, scarce block signed and with Holcombe certificate (1995), Mi. € 720,-- + 100% for MNH (Image)

1928, Colombia issue 'SERVICIO DE TRANSPORTES AEREOS EN COLOMBIA' 10c. blue-green with red opt. 'ECUADOR / PROVISIONAL / 50 Cts. 50' block of four from lower margin with variety 'NO CURL on T of Cts.' on the two right hand stamps (only 100 copies of this variety printed), fine and fresh mint never hinged, scarce block signed and with Holcombe certificate (1993), Mi. € 720,-- + 100% for MNH (+ variety) (Image)

1929, Registration stamp 1s. rose ‚Cathedral of Quito‘ with black opt. ‚R‘ in a block of 25, mint never hinged with typical uneven gum, scarce block! Mi. € 2.500,-- + (Image)