Upgraded Dual Extruder: Dual gears and dual pneumatic combined extrusion structure, large extrusion force, enhanced feeding intensity, ensuring smooth feeding. The double gear rotation design locks the filament, which is beneficial to improve printing quality and reduce filament slipping, high-speed extrusion or retraction, better pressure to push the filament into the printer, less easy to lose steps, faster printing speed Compatibility: Double gear mk8 extruder, perfect replacement for 3D printer CR-10/ CR-10S/ CR-10S Pro/ Ender 3 (initial version)/Ender 3 v2/Ender 3 pro/Ender 5/Tornado, etc. 1.75 mm filament (Set only for 3D printers with motor shafts exceeding 20mm, please measure the shaft length before placing an order.)