I bought these nothing special but I just like the look of the coins. I don't really have an area of collecting but if it strikes me right I will pick it up.
It's K B K for Κύζικος = Cyzicus, an ancient city on the southern shore of the Sea of Marmara. B is the Greek numeral for 2 It means that this coin was minted in the Officina 2 of the Cyzicus mint.