This is a genuine manufacturer-sourced replacement hardware that is commonly utilized on Craftsman lawn and garden equipment. A lock nut is a type of nut that resists loosening when it is properly threaded onto a bolt. This is a standard hardware which has multiple applications depending on your unit, make sure to check appropriate diagrams for correct location and use of this item. Please note this durable metal lock nut is sold individually.
OEM stands for Original Equipment Manufacturer. Simply put, this means that the company who made your appliance is also supplying the replacement part for it.