Indeed, i's the rear part of the Phantom engine, instead of the front. Checking my saved threads on my other machine, I realized at least a couple of people have spotted this, e.g. Matt Meyer. On Matt's build the parts look like they're cast in the same resin as the rest of the kit, but the piping is improved - actual piping instead of the flat ridges you get on the actual engines. Does Mike S provide this part if you ask for a Red 5 kit?