This is a genuine OEM sourced component which is specially made for use with Fein power tools. It is an identical replacement for a missing or a faulty locking ring that was installed on a new unit. The ring allows a part to be secured to a shaft. Please make sure to refer to the appropriate diagrams of your model for the exact location a...Read morend application of this hardware. Keep in mind this high-quality locking ring is made of durable metal and is sold individually. Note, you will need lock ring pliers to secure or remove this component.