12mm Bore Timing Pulley 2mm Pitch 40 Teeth 6mm Wide Belt Groove for 3D printer GT2Description 2mm pitch (GT2) 40 teeth 12mm bore 6mm width timing Belt With 2 set screw to secure to the stepper motor shaft. One pulley Most Common Application12mm shaft stepper motor and fits 6mm width timing belt 2mm PitchUsed on Kossel Delta and other similar 3D Printers RepRap