Usage Tips:Product descriptionItem Package Quantity:10[Fits multiple Black +Decker string trimmer models]: LCC140, GH400, GH500, GH600, GH610, GH900,GH912, ST6600, ST7000, ST7200, ST7700, ST7701, ST8600, ST9000, CST1000, CST1100,CST1200 and more1.[Compatible with Black+ Decker Trimmers]: Designed for use with Black & Decker auto feedstring trimmers, This spool and cover are Black & Decker Spool a perfect replacement 30-foot factory-wound replacement spool features a 0.065-inchdiameter line.2.[ Feed System Replacement]: Eliminatestime spent hand-winding string trimmers, compatible with Black+Decker stringtrimmer and utilizes centrifugal force to feed the trimmer line as it isneeded.3.[Enhanced material]: Premium 0.065-Inchdiameter enhanced nylon line, supports fast cutting and longer lifetime. (Note: OnlySuitable for tender weed grass. Tough and strong weeds please use blades totrim)4.[Packageincluded]: 6 replacement trimmer string spool, 2 replacement spool cap, 2springs (zhongchengdaye)