Application:Fit for: grip the filament of your 3D printer.Deep grooves give good hold for 1.75mm filament. Specification:Use For: MK7 / MK8 3D printerMaterial: Stainless SteelOuter Diameter: 12mmHeight: 12mmShaft/Bore: 5mmTeeth: 40Thread Size: M3 Package Content:3 x Drive Gear