compatible with RC-100 Replacement spool cap designed for use with trimmers. (Spring not required for cordless trimmers.) Automatic feed spool Measures 3.5-by-1.5-by-3.5 inches; weighs 1.6 ounces Fits GH400, GH500, GH600, CST1000, CST2000, NST2018, ST7000, ST6600, and ST7700 Original quality 3-year warranty Compatible with RC-100. The WeToolPlus Replacement Spool Cap and Spring is designed for use with string trimmers that utilize an automatic feed spool. This product fits BLACK+DECKER AFS models GH400, GH500, GH600, CST1000, CST2000, NST2018, ST7000, ST6600, and ST7700.