I wanted a spool holder that would hold spools of all sizes. I also wanted a spool holder that doesn't require any modification or screws to be removed from the printer. This holder slides into the center slot that are under the AMS that is just empty space. It is a great way to quickly install and remove a spool holder if you want it out of the way. It will require glue so that the smaller threaded part is held in place and the bigger part will thread onto the smaller part.