The printer comes with a spool size which fits in the printer. This filament comes from the manufacturer, but we don't offer it in our shop.
If you are looking for the same size & quality like the filament that came with the printer, please try the filament from Flashforge:
If you want to use Monoprice filament or other types, we recommend printing with an outside spool holder:
With the spool holder you can use any filament you would like.