I don't have one, but to me the hot end looks like a Jhead, which has a body formed from PEEK as DBFIU mentions. They also have a PTFE liner tube. Browsing a bit, I see more than one approach to the jhead. Some have a removable nozzle, some have a nozzle that is machined out of the same brass block as the heater block. If the nozzle part doesn't have a hex pattern to it that could be grabbed with a wrench, you have the single machined block type.