3 pcs "Chway" brand String Trimmer Replacement Spool Cap Cover (Cap Model: 2958002), compatible with multiple Greenworks string trimmer models including #2101602, #2101602A, #STBA40B210, #BST4000. Please verify your model number before purchase. Professional design – These replacement caps are round green caps with a diameter of 2.95 inches and a height of 1.265 inches. The spool cap cover is engineered to securely hold the spool in place, ensuring proper trimmer function. Constructed from high-quality materials – Made of PA66 (Nylon) + G30 (Glass Fiber). The addition of glass fiber enhances stiffness, wear resistance, and heat resistance compared to standard ABS plastic caps, helping extend product life. To confirm compatibility – Locate the model number on the product nameplate of your string trimmer or refer to the user manual.