Titan adaptor for using 3mm ID reverse-Bowden tube

This is a small adaptor meant primarily for using 4mm OD/3mm ID PTFE tubing for a reverse bowden tube at the input of a Titan extruder. I use a reverse-bowden arrangement to eliminate issues with filament spilling off a nearly-full spool and to get cleaner prints by preventing irregular jerking of filament from the spool due to nozzle movement (see included diagram). The usual 4mm OD/2mm ID PTFE tube will work for that, but using a 3mm ID tube makes threading the filament through a long tube