uxcell 5M 12mm Bore Timing Pulley Aluminum 20T 12mm Bore Diameter 16mm Width Belt Material: Aluminum; Durable and practical. Teeth: 20; Bore Diameter: 12mm; This timing belt pulley fits a 15mm timing belt. Widely used in milling machines, CNC engine lathes, gear shapers, hobbing machines, drilling machines, or other mechanical transmission occasions. Package Contents: 1 x 5M 12mm Bore Timing Pulley Made of high-quality aluminum. I am selling this unused because the size did not fit after purchase. All tags and accessories are included. The condition is like new. <br />Widely used in milling machines, CNC engine lathes, gear shapers, hobbing machines, drilling machines, or other mechanical transmission occasions.