A single or dual spool holder using the original (Tenlog.. but others may work too) stock spool holder upright and secured with the collar. For 1kg spools of filament. It is important to make the threaded part and 5 or more layers of the shoulder with 100% infill or the part may fail when the collar is tightened. Make sure the collar bevel faces outward and carefully tighten with pipe wrench.