Chicago Die Casting 1/2" Bore x 2" Diameter Single V-Groove Die Cast Pulley is for use with 4L or 1/2" x 11/32" belts. It has a hollow head set screw that allows for easy installation and removal. This pulley is made of die cast metal, which makes it durable and long-lasting. It is also available in a variety of sizes to meet your needs.