When, I first heard of them, I heard plastic. I thought they had to be roto-cast, but did not know they could do the skins filled with the other stuff. I knew it had to be tough, I've seen a lot of kayakers, "play" in some serious water with their plastic boats. But I thought the plastic might not be rigid enough for a much bigger boat. Didn't get to ride in it, but it certainly doesn't have the thumping that the fiberglass drifters do - certainly seems much quieter when you slap it around a little while it is still on it's trailer. But battleship gray?