6.35mm Bore Aluminum Timing Pulley5mm Pitch 12 Teeth 15mm Wide Belt Groove for 3D printer HTD5MDescription 5mm pitch (HTD)12 teeth6.35mm bore15mm width timing BeltWith 2 set screw to secure to the stepper motor shaft.One pulleyMost Common Application6.35mm shaft stepper motor and fits 15mm width timing belt 5mm Pitch HTD-5MUsed on Kossel Delta and other similar 3D Printers RepRap