Nice presentation 👍. Maybe you should mention if the prices you show are for mint or used stamps. But what I don't understand is you mention different prices than is shown ???!!! And one other thing I must comment (at 03:55). The dark-violet stamp (1867, 25 Cent, King Willem III) is in the official Dutch NVPH-catalog (issue 2018) mint priced for 125.000 € , and not 5800 € !!! Just a little difference, isn't it ???
