The Exmark 126-9189 Lawn Mower Flat Idler Pulley maintains proper belt tension and guides the drive belt for smooth operation in compatible lawn mowers. It rotates freely as the belt passes over its flat surface, supporting consistent belt alignment and efficient power transfer between connected components. Installed within the mower deck or drive assembly, it works with the belt syst... https://www.wholetoolbox.com/exmark-126-9189-lawn-mower-flat-idler-pulley/126-9189.html