Made a topcover to facilitate a second spool and hold a PTFE tube inlet for both spools. Originally, when Z goes down; filament slacks. This used to tangle filament for me if the spool is very full. putting the PTFE inlet in a fixed position resolves this.

Of course this does not change material like the AMS but it is easier to swap filament by pushing pulling the filament. 

Also holds nozzles in the holes at the top.

made this out of PETG but i wouldve appreciated the stiffer PLA here.

Bambu labs sells extra tubes and ptfe adapters. i used 1/8th 4mm connectors instead of M6 connectors. Let me know i you want a design change for threads.