I have a bunch of them, the F.E. is part of a series including F.A., F.B., F.C., F.D., F.E., and F.F. On the opposite side, there is a number that corresponds to the second letter A=1, B=2, C=3, etc. I still don't know who made them, but I believe they were from Europe. They post-date 1907 and likely pre-date the 1930s. The ones I have are from 1907-1916.