"American Letter Mail Co." LOCAL POST stamps set of six so-called "trial color proofs". Mounted (hinged) on small printed slip in the manner they seem to have been distributed. Despite the text on the slip, these are actually reprints. See Scott #5L1 footnote. Six colors: Red-Violet, Ultramarine, Red, Green, Brown, and Orange. No gum as "issued". While these are certainly not rare, they are quite interesting and unusual. I have seen them sell for $35 on up to $100 per set!
ACTUAL item.