I just called RTpartsco for these heads. He stated that there are only 20 sets left nationally. He has sold many in recent weeks. He asked how I heard about these. He just shipped a set to Russia and Australia. I asked if he knew what the "suppersion AB" was and he did not know, but is going to ask. He doesn't think he will get an answer to be honest. I will still call Glendora in Cali later today.
