The Polybox is a drybox from Polymaker. Unfortunately, sometimes the filament spool does not rotate smoothly, which causes the printer to pauze or even ruin the...Show more print. This filament spool holder lets you fit your filament spool easily, secure it with the included hand screw and let your filament spool rotate smoothly when your printer continuously feeds material. Best printed in PLA, Tough PLA or ABS. Of course you can use other materials to your preference.