"This Phoenix 4 1/4in. V Idler Pulley Wheel with 5/8in. bore offers smooth operation, high speed performance and long life. U.S.A. Bore Diameter in. 5/8, Material Type Metal, Compatible With Outdoor power equipment, Pulley Diameter in. 4 1/2, Part Type Pulleys, Product Style V idler pulley. 5/8in. bore idlers can be reduced to 3/8in. or 1/2in. with bushings Precision ground bearings with double seals protect against dirt and moisture for high speeds and long life"