3 pcs "Chway" brand String Trimmer Replacement Spool Cap Cover (Cap Model: 2958002), compatible with multiple Greenworks string trimmer models including #2101602, #2101602A, #STBA40B210, and #BST4000. Please verify your model number before purchase as compatibility is limited to the listed models only.Professional design – These replacement caps are green, round, 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 from PA66 (Nylon) + G30 (Glass Fiber). The addition of glass fiber enhances rigidity, wear resistance, and heat resistance compared to standard ABS plastic caps, helping to extend product life.To confirm compatibility, locate the model number on the product nameplate of your string trimmer or refer to the user manual. Pre-sale support is available for any compatibility questions.