The Hustler 604491 is a genuine OEM idler/tensioner pulley designed for a wide range of Hustler zero-turn mowers and lawn tractors. This critical component maintains proper belt tension, preventing slippage and ensuring efficient power transfer to the mower deck or other attachments. Constructed for durability, it features an outer diameter of 139.7 mm, an inner diameter of 17 mm, and a width of 30 mm, providing reliable performance and a precise fit for compatible models.