Spool Center Holder

Spool Center 20mm ID 52mm OD 50mm Height
Might want to scale up a bit if the inside is not enough for your spool. It will squeeze several millimeters when inserted into the spools if needed. PETG filament or maybe ABS should work fine for these type of models, pretty sure if the model is printed on PLA would work as long as the center is not squeezed in too much and you just want something to fit some sort of rod on a spool holder to have the spool centered.