Tonga 1920-35 set of 9 to 1s Specimens, SG55s/63sTonga 1920 35 set of 9 to 1s, overprint (2d type D9, 2d bicolour to 1s type D12) or perforations (d and 2d ultramarine type D19, 1d type D20) "SPECIMEN" for Universal Postal Union (UPU) distribution, SG55s 63s. A fine quality mint set with large part original gum to full original gum, benefiting particularly from very fresh colours. As to be expected there are a few minor blemishes (the 2d ultramarine with a few short perforations and minor gum