I made this to hold a secondary filament spool on my Bambu Lab A1 printer. To fit this, you need to take out the rubber caps on the other side of the Bambu spool holder. You will also need an extra PTFE tube to guide the filament to the tool head.

How do you use it? Simple! You can only use one filament at a time. This fixture simply makes it easier for you to unload, load, and leave the spool on the printer when not in use.