This variable speed pulley is a genuine MTD part, sold individually. This variable speed pulley can be used as a replacement part in a lawn mower. The purpose of a variable speed pulley in a lawn mower is to regulate and manage the speed at which the motor runs so that the speed can be kept within a stable range for the safety of the operator of the appliance.The variable speed pulley in a lawn mower might have to be replaced if the variable speed pulley can no longer properly manage the speed of the lawn mower. This could occur if the variable speed pulley suffers damage from general wear and tear with long-term use or as the result of an accidental collision with a hard object that warps the variable speed pulley beyond functionality. This replacement should be executed in accordance with the proper instructions sourced from a relevant appliance manual.This component is a genuine OEM replacement part sourced directly from the manufacturer. It is sold individually. This variable speed pulley is compatible with the following outdoor appliance brands: MTD.