XL Type 21T 22T 23 Tooth BF Synchronous wheelType: XLPitch:5.080mmTeeth Number: 21T 22T 23 ToothBore:4/5/6/6.35/8/10/12/14/15/16/17/18/19/20mmKeyway:3/4/5/6Material:Aluminium AlloyFit for Belt Width : 10/13/15mmPulley Package :1pcsUse For : CNC mechanical device Synchronous Belt Pulley;3D printer Transmission Pulley;DIY mechanical device Gear.