The Simplicity 1731974SM is a genuine OEM idler pulley designed for use in mower deck assemblies on a wide range of Simplicity and Snapper riding mowers and zero-turn tractors. This essential component maintains proper belt tension, ensuring efficient power transfer and smooth operation of the cutting system. With an outer diameter of 114.3 mm (4.5 inches) and a bore of 15.875 mm (5/8 inch), it is built to OEM specifications for durability and precise fitment, contributing to the longevity and performance of your lawn care equipment.