All the specs on all the Thors say the hosts are AL. I know the brass module isn't a good sink but Paul are you sure? Did you try a magnet on yours, as I don't believe its stainless if the magnet were not to stick.\n\nI checked it and I was mistaken. I believe I was confusing this with the Sanwu host. Still, it has a small brass heat sink. Not nearly enough for long run times.