Many of the Exporta Stamps of Mexico are rather plain - even ugly to some people. That's what I thought until just recently. However, there is much more to them than meets the eye. There are 14 distinct paper types. There are perforation varieties, color varieties, and even plate flaws! There were three currency inflations during the time the Exportas were issued and thus, many denominations. This also means that there is a lot of interesting Exporta postal history. As you can see, there is a lot to study with this series!
I just recently started studying them, so I have a lot to learn. I've been reading all I can about them in various magazines and have come up with some very helpful information. I am currently looking for any mint ones I can get and any used ones on cover. I have lots of stamps to trade, so please write to me if you are interested in trading with me.