SUERW Line String Trimmer Replacement Spool, [13-Pack] 30ft 0.065" Replacement Autofeed Spool for Black+Decker String Trimmer [12 Replacement Line Spool, 1 Trimmer Cap][Compatiblity]: Suitable for GH400, GH500, GH600, GH610, GH900, GH912, ST6600, ST7000, ST7700, CST1000, CST1200, CST2000, MTC220, MTE912, NST2018, NST1118, NST2118, LST220, LST300, LST400, LST420, LST136 [Auto Feed System Replacement]: The trimmer replacement spool is compatible with Black+Decker string trimmer and utilizes centrifugal force to feed the trimmer line as it is needed. The auto feed system replacement spool eases the tedious work of hand