I'm using 1/4" tubing between my filament storage box and the printer. Without this guide, the tubing adds friction at the stepstruder end.Print the part at 100% fill then drill out the holes for a snug fit.I tapped the unused feed hole in my MK7 stepstruder to mount the part.WARNING: After doing this, disassemble the stepstruder feed mechanism to remove any plastic particles that otherwise may clog your extrusion nozzle.Undoubtedly someone will now educate me on why I shouldn't have messed with that second hole.... :-)