M3D recommends printing and utilizing an external spool holder. We have provided several links here. It's highly recommended to print your external spool holder as one of your very first prints. The external spool holder will allow you to utilize a wide range of different size filament spools, as well as optimize your printer's performance.
Here are several looks to choose from:
The Rifle Spool Holder
The Original Spool Holder
Whichever look you choose, your external spool holder will be an extremely useful addition to your M3D Micro Series printer.