Die-cast. A section for 4L or 1/2" x 11/32" belts. All pulleys are furnished with hollow head set screws. The 146 3-step pulley measures 2-1/4", 3" and 3-3/4" outside diameter. The 141 4-step pulley measures 2", 2-1/2", 3-1/2", and 4" outside diameter. No. 146-5: Outer Diameter: 2-1/4", 3" and 3-3/4", Bore Size: 1/2", Type: A No. 146-6: Outer Diameter: 2-1/4", 3" and 3-3/4", Bore Size: 5/8", Type: A No. 146-7: Outer Diameter: 2-1/4", 3" and 3-3/4", Bore Size: 3/4", Type: A No. 141-5: Outer Diameter: 2", 2-1/2", 3-1/2" and 4", Bore Size: 1/2", Type: A No. 141-6: Outer Diameter: 2", 2-1/2", 3-1/2" and 4", Bore Size: 5/8", Type: A