DD Direct Drive 3D printer extruder 3mm filament

This is assembly of DD extruder for FDM 3D printers. It is capable to
work with ABS, PLA, PC, PET, PVA and also NinjaFlex filament.
https://www.youtube.com/watch?v=WZZODwPEQWo

If you want to know how to make driving pulley for this extruder look at this video https://www.youtube.com/watch?v=0JIviB6cqhI