Uxcell a11110100ux0114 15/64" Bore 1/5" Pitch 21 Teeth Timing Pulley 21XL for XL037 Belt, Metal Product name: timing pulley; model: xl; material: metals Color: silver tone; number of tooth: 21; pitch: 5.08Mm/ 1/5 inch Side lug diameter: 23Mm/ 0.91"; bore diameter: 6Mm/ 15/64"; fit belt width: 11Mm/ 0.43"