Internal diameter of cardboard spool hole must be 55mm, the adapter is press fit into both sides, with spikes that bite into the cardboard for a secure connection.

Designed for Plexiwire small 300g spools, which are just under 15 cm in diameter. With the same internal diameter should be compatible with other brands.

Printed at 0.2mm, 3 walls/top/bottom takes 45g of filament per side and about 1h 10m of print time.