This replacement grass trimmer line spool set is designed for Worx weed eater. With the auto feed system, the replacement spool eases the tedious work of hand-winding spools. The spool compatible with Worx utilizes centrifugal force to feed the trimmer line as it is needed. The WA0010 features a revolutionary and innvoative DNA2 DoubleHelix line that is superior to the standard round line by producing an improved cutting action, which helps to keep grass healthier and greener. Key Features: This replacement grass trimmer line spool set is designed for Worx weed eater, made from a patented copolymer nylon resin and synthetic material designed with an oval aerodynamic shape. This patented design increases edging life up to 25-percent compared to normal use conditions. his resin line is softer, allowing for the line to stretch and cushion on impact with hard surfaces. It has over 100 lbs of tensil strength compared to old lines that only offer 68 lbs of strength. This trimmer line is durable and flexible for longer life. This replacement line is compatible with the following WORX trimmer and edger models: WG150, WG151, WG151.5, WG152, WG153, WG154, WG155, WG155.5, WG156, WG157, WG160, WG160.1, WG160.2, WG163, WG165, WG175, WG180   With the auto feed system, the replacement spool eases the tedious work of hand-winding spools. The spool compatible with Worx utilizes centrifugal force to feed the trimmer line as it is needed. High-Quality 10ft/ 0.065"" weed eater edger line string easily cuts through grass and weeds. Package Included:   10x replacement weed wacker string line spool  2x replacement cap