0.065 inch cordless trimmer spool line diameter to perfectly fit the line hole. 10 foot spool line length provides greater mowing range. Compatible with original Worx model parts No. WA0010 and Cap WA6531 GT. Replacement edger twine spool line was made of premium raw material, strong enough ABS spools, of flexible nylon yarn strings, strong enough for long life. The range of electric weed eater spools use centrifugal force and aerodynamics to reduce drag and enable fast cutting. CNC trimming and winding saves time of tedious manual winding, reduces damage to the trimmer, and prevents jamming during mowing. Replacement cover to fix the spool and stay safe while mowing Centrifugal force and fast cutting when in use, recommend wearing eye protection and long pants to avoid unnecessary injury. And this cordless grass eater parts refill is only suitable for soft grass. It will be recommended to use blades to cut strong weeds. Compatible model: WG163, WG163.4, WG163.9, WG160, WG160.4, WG160.3, WG160.1, WG160.2, WG155 , WG155, WG150, WG151, WG151.5, WG151.5, WG155, WG155, .5, WG156, WG157 WG170, WG175, WG180, WG954, WG921