DualDrive gears for 1.75 mm filament,Precision custom cnc machined with extreme precision guarantees that you get the grip you always wanted. The gears are treated with hardened steel. Greatly improved the durability and reliability of gears. The extruder controls the filament very well. Package list All gears are stainless steel. 1.Superior quality pulley WITHOUT the lock screw X 1 2.Superior quality pulley with the lock scre X 1 3.Pulley shaft X 1(3MM*20MM) 4.Pulley bearings X 2 5.Stainless steel square nut X 2.