This hex nut is designed for use with select trimmers and mowers. It is a standard hardware part that may have multiple applications depending on the type of unit and model. The nut is typically used to secure engine components or housing elements to provide safe use of the machine. These nuts are durable, but they are small and can become lost during other repairs. The constant exposure to vibrations and use can also cause them to strip or become damaged over time. Either way, a replacement with this genuine hex nut will resolve the issue and get equipment back in working order. This genuine OEM hex nut is manufactured to exact standards and sourced from the manufacturer. It can be used with trimmers and mowers from RYOBI, MTD, Bolens, Troy-Bilt, Yard Machines, Huskee, Yard Man, and Cub Cadet. Check the parts diagram for exact application and location of this nut and note that it may have multiple uses on select models. This hex nut is sold individually, and additional nuts will require the purchase of multiple pieces. In order to replace this nut, a hex socket wrench and driver will be required. Always wear gloves for safety.