This is a housing for bowden extruders to allow using my Ultimate Filament Colorer method without coloring the inside of the bowden guide tubing. Uses two Bowden adapters: https://www.ebay.com/itm/5pcs-1-8-Push-In-Fittings-For-4mm-OD-PTFE-Tube-For-bowden-extruder-1-75mm/172066287453?hash=item280ff32f5d:g:WcUAAOSwNSxU1FEm Ultimate Filament Colorer: https://www.thingiverse.com/thing:312327