Also referred to as a Lock Nut or Flange Lock, this nut is designed for use with various lawn and garden equipment. The purpose of this part is to hold parts in place while resisting loosening when properly threaded. It is sold individually, not as part of a kit or assembly. It is black, made of metal, and is found in a variety of locations. Refer to your owners manual to determine if this is the correct part. This part will need to be replaced when it is weak or broken. The symptoms experienced when this part breaks will depend on its location. You will need pliers to complete this repair. Customers rate this repair as Easy.