These are the parts to make a dual filament runout sensor.
This dual Filament runout sensor is used to stop your 3D printer automatically when the filament is depleted.
The sensor works on all 1.75mm filaments, and switches to GND when one of both filaments is depleted.
The green LED lets you know that filament is out.
On the front are 2 woolen filament cleaners (this will save you a lot of filament jams)
On the back are 2 quick tube connects for 3x5 PTFE tubes to guide your filament to the extruder
The printed parts are not included. You can print them yourself, or order them with the parts. Here is a link to the files.