This OEM Locking Ring holds components or assemblies onto a shaft or in a housing/bore when installed in a groove. Installation is rated as "Easy" by customers and will require pliers. The part secures the drive pinion gear to the drive shaft, and if broken due to wear/fatigue/damage, it will need to be replaced.
An authentic replacement part that is specially manufactured for use with Toro lawn mowers. This is the knob that is secured to the heigh-adjustment arm assembly, for correct location and uses make sure to check appropriate diagrams of your model. Please note this durable plastic part is sold individually.