The Black & Decker string trimmer replacement spool provides a 20-foot replacement line for use in your bump feed string trimmer. This factory wound spool offers maximum reliability and eliminates the hassle of having to wind the spool yourself. Using the correct diameter line is critical to the performance of your string trimmer -- this spool features a .065-inch diameter line. This replacement spool is designed for use with the following Black & Decker string trimmers: #ST1000, #ST3000, #ST4000, #ST4050, #ST4500, #ST5000, #GE600, #ST200, #ST300, #ST400, #CST800, and #ST6800. It is backed by a 2-year full warranty.