It's may have a flywheel to keep it consistent speed. It kind of looks like one at the top. The fact that they were confident enough to not wear eye protectio

It's may have a flywheel to keep it consistent speed. It kind of looks like one at the top. The fact that they were confident enough to not wear eye protection is one more thing that makes it impressive. I mean, certainly they have an insurance company that would want to see that they are being safe, right?