This thing works awesome! number one benifit is when you remove the filament from the extruder or cut the end off, it DOESNT SPRING BACK AND ROLL UP/OUT! keeps your rolls nice and neat. I made 3 nubs so you could have 3 spools and switch between filaments easy during prints and not need to slip the filament thru the little holes in the spool to keep it neat.

needs 1/4 OD vynal tube, available at any hardware store for about .13 bucks a foot. iirc 2 feet was perfect length, you want it to loop lazily around to the extruder at its lowest point. if it is too short it will bend sharply and there will be a lot of drag.

this is meant to be used with the standard MM1.5+ spool mounts, thingiverse.com/thing:21068

The drag thru the tube is not negligible, it does resist pulling. I have had 0 feed issues because of it, however if your extruder is not a happy camper already, I suggest you hunt down some low friction tubing, or omit the tubing all together. Even if you just run the filament thru the vertex w/ no tube, it serves the purpose of stopping it from unspooling on the spool when loose. Just reverse the direction of the roll and come down from the top instead, and it works fine with ABS, PLA is not always so happy about the corner tho. if I angled it itw ould work, but I am 95% ABS, so I don't care.