This is a simple spool holder I originally designed for my flsun 3d printer which is built from 2020 aluminum framing. The holes are designed for 4 mm screws which are supplied with the printer kit. This simple spool holder can be installed in any orientation the user would like. The intent for the reel holder was to be a zero-clearance fit, but it ended up being a tight enough fit to hold it in place or replace with a different holder for alternate, or multiple reels.