DIY Reprap Bulldog All-metal Extruder For 1.75mm Compatible J-head MK8 Extruder Remote Proximity For 3D Printer Parts

Description: Extruder gear inner bore: 5mm. ( You can change according to the actual situation,for example, use MK7 Bore 5mm gear) Designed for 1.75mm filament,Pipe outer diameter need