This is a spindle for 40mm spools.Combine with some Tinkertoys and you've got yourself a handy way to feed another color into your printer without removing existing spools.http://zheng3.com/2012/07/11/complexity-is-free/
Seej patient zero. 3D Designer, artist, worst programmer ever. Mostly illiterate, but has minimal competence in spoken Mandarin. Not real clear on Ohm's law.