I know a guy that bought these blades off of ebay. He was telling me what a great deal he got on carbon fibre (or carbon graphite) blades, so I went over to his place and had a look at them. I am not a materials expert but they sure looked like plastic to me. Maybe they have trace amounts of carbon something in them, but the felt like plastic, flexed like plastic, weighed about the same as plastic, and looked like plastic. When I told him I thought the blades were plastic the guy wasn't very happy, he still hasn't put up the mill yet so I can't comment on the blades performance.