Compatible with AF-100 The LBK string trimmer Auto Feed System (AFS) Replacement Spool eases the tedious work of hand-winding spools.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 string trimmers including: GH400, GH500, GH600, GH610, GH900, GH912, ST6600, ST7000, ST7700, CST1000, CST1200, CST2000, MTC220, MTE912, NST2018, NST1118, NST2118, LST220, LST300, LST400, LST420, LST136W