This is a high-quality retainer that is typically used in string trimmers. It is made of durable metal and fits in the area between the outer spool assembly and the spring on the trimmer. The purpose of the retainer is to ensure the spool stays in the correct location while the string trimmer is being used. This component can become damaged, break, or be lost and will need to be replaced in order to be sure the spool is supported and secure.If there is an issue with the string trimmer retainer, it can cause excessive noise during use. It also may prevent the trimmer from starting if other components are affected. A wrench and work gloves may be required to replace the part. Gain access to the retainer and remove it using the wrench. The new replacement part can be installed in the same place. Reassemble other parts, and the trimmer will be ready to use.This retainer is designed to fit string trimmers manufactured by Craftsman, Cub Cadet, Ryobi, Troy-Bilt, Yard Machines, Bolens, MTD, and Yard-Man. It is sold as an individual part. It is an authentic OEM replacement part that is sourced directly from the manufacturer.