What are the advantages of Redrex Dual Gear Extruder? 1.The dual gears grip filament firmly to fix a problem with filament slipping. 2.To address the gear eating into the arm, Redrex Dual Gear Extruder comes with two washers between the gear and the arm. 3.This aluminium alloy extruder works great with 1.75mm filament,such as TPU/PLA/ABS/Wood/Hips/..