The Phoenix 1in. x 4 1/2in. V-Belt Pulley is a heavy-duty split steel pulley fabricated from solid steel stock. Replacement for lawn and garden, farm and agricultural, and industrial equipment. U.S.A. Heavy-duty split steel construction4.5in. O.D.1in. boreFor 1/2in. or 5/8in. V-belt1/4in. standard shaft keyway size2 set screws are factory inserted for strength