uxcell Aluminum 3 M 20T 3mm Bore Timing Idler Belt Pulley Synchronous Wheel with Bearing for 15mm Belt Material: Aluminum Alloy; Durable and virtually. Teeth: 20; Bore Diameter: 3mm; Suits to the timing belt which is 15mm width. Used widely in milling machine, CNC engine lathe, gear shaper, hobbing machine, drilling machine or other machinery transmission occassions. Package Includes: 1 X 3 M 3mm Bore Timing Pulley