This V-Groove Drive Pulley works both as an OEM replacement and as a general purpose pulley for power transmission such as compressors, industrial fans, lawn mowers, snowblowers, and electric motors. It has a hub attached and the inside diameter is 20mm. There are no set screw holes. This part is Painted Black to prevent rusting. Additional Features: Made of Steel Works with 4L/A|5L/B belts Direct OEM Replacement for: John Deere: AM121832