The cone of this driver is made of bamboo fibers. It’s a very nice driver and well made. I have been enjoying them on open baffles (on top of H-frames for bass support) lately. They sound great if you like a darker sound. I prefer these with tweeters but they have an extended treble response that’s muted and soft. Overall, one of my favorite drivers. In a small ported box it sounds like a a good two way speaker. Occasionally I feel the driver has a mechanical sound that separates it from the best drivers I’ve heard.