rock tumbler machine. I used this to create powder aluminum. It is not a good machine for that because the RPM is wrong. After running continuously for months it made only a small amount of poor quality black powder mixed apparantly with some rubber from the containers. It is probably good for rock tumbling etc. There are 2 containers and one of them has worn the lid very thin and broken. It still holds the contents ok. The other container is much better. It runs but needs cleaning and tlc.