It consists of one side of an empty Prusa spool and a holder for 250g spools. It works with the Prusa Mini Base without longer feet.

The screw is simply pressed into the side of the spool instead the cardboard roll. The coil is held with the nut.

I printed it from Prusament PETG. 0.2 layer height with 15% Gyroid infill.

You need only one nut. Choose the one that best fits your filament spool.