It's a tool to adapt the tiny spools of the toy « Kumi Kreator », simply fix the hex side in a drill, put a spool on it (no hardware required) and refill your spools in seconds!

You need to run reverse your drill to get the spools filled the same way as or originals, I don't know if it is does matter or not.

You'll find other Kumi Kreator stuff in this collection

Print instructions

PETG, 0.2mm layer height