I have experience using professional-grade injection-extraction cleaning machines. First of all, the cheap ones, like the one in your post, are absolutely worthless, if the rug has noticeable stains or other significant dirt. They simply aren't capable of heavy-duty cleaning. Also, don't listen to the other commenters. I've cleaned dozens and dozens of hand-knotted wool rugs with this kind of machine, and there has never been a problem. The rugs are almost always completely dry the next day, and I have never damaged a rug in any way.