I have broken countless cutoff wheels so I am well aware of how fragile they are. I wanted to find a way to keep the one that is mounted safe as well as the spares. These are screw top containers that hold both. One of the containers will hold all of the spares neatly stacked. It can be made taller or shorter by cutting out the middle section in programs such as TinkerCAD. The other container has a hole in it and it will keep the mounted cutoff wheel in place and stop it from breaking. One lid has a part that will hold it down so it does not shake around too much. While the other is flat at the top for the spare wheel storage. The spares container can also hold buffing wheels of the same diameter or smaller.