Ultimate Filament Guide for Robo3D

After trying many options I believe this is the simplest and best filament guide. It fits directly into the square hole that contains the bolt for the X axis belt.

It seems to work really well.

It is designed to fit loose, so I recommend wrapping the bottom with a layer or two of masking tape. This created a firm fit, but can be removed to be able to access the bolt below it.