The BLACK+DECKER string trimmer Auto Feed System (AFS) Replacement Spool eases the tedious work of hand winding spools. Designed for use with Black & Decker auto feed string trimmers, the 30 foot factory wound replacement spool features a .065 inch diameter line utilizes centrifugal force to automatically feed the cutting string while eliminating bumps and hitches. The AFS replacement spool is compatible with most AFS BLACK+DECKER string trimmers including: GH400, GH500, GH600, GH610, GH900, GH912, ST6600, ST7000, ST7700, CST1000, CST1200, CST2000, MTC220, MTE912, NST2018, NST1118, NST2118, LST220, LST300, LST400, LST420, LST136WThe BLACK+DECKER AF-100-3ZP String Trimmer Replacement Spool 3-pack erases the tedious work of hand-winding spools. Designed for use with BLACK+DECKER auto feed string trimmers, the 30-foot factory-wound replacement spools feature a .065-inch diameter line that utilizes centrifugal force to automatically feed the cutting string while eliminating bumps and hitches. The AFS replacement spools are compatible with the following BLACK+DECKER string trimmers: #GH400, #GH500, #GH600, #ST6600, #ST7000, #CST1000, #CST2000, #NST2018.