Uxcell a13123000ux0537 Stepper Motor 30 Teeth 6mm Bore XL Type Aluminum Timing Belt Pulley Product Name : Timing Pulley ; Number of Tooth : 30T ; Pitch : 5.08mm/1/5'' Bore Diameter : 6mm/0.24" ; Top Diameter : 38mm/1.5" Overall Size : 53 x 25mm/2.1'' x1''(D*H) ; Fit Belt Width : 11mm/0.43"