Print the STL which includes all the parts already plated in the correct orientation. You will also need: One(1) - M5x12mm Socket Head Screw One(1) - M5x30 Button Head Cap Screw Two(2) - Extrusion T-Nuts Three(3) - 608 Skate Bearings. You can also put a little felt on the underside of the upper guide. Then the top ring of the spool can slide on that felt and create some artificial resistance. This is helpful if you have very stiff filament that likes to unravel with low resistance spool holders.