I have slowly been collecting these, (they are extremely popular). I just got a third type today at CNG: It is a Hadrian hemidrachm. I liked this one for the clearly visible "ramp" to the side of it, a feature often lost on these. Here is an excellent website containing the types: http://ancientcoinage.org/lighthouses-of-alexandria.html Of the major types, I have the drachm with Isis right, the Commodus Tet, (mine is actually better than on the website, I got lucky at a coin show), and now this type. I am missing Isis left and the issue with only letters on either side of the Pharos. I am not nearly advanced enough with this mini-collection to worry about every reverse/ruler combination, (yet). Maybe someday.