Each spool in the Worx WA0207 3-piece Replacement Trimmer Line and Spool Cap kit comes pre-wound, so you can just pop them into your trimmer and get to work. Each spool contains 10 ft. of string, so each 3 pack we send has 30 ft. of line. Trim and edge as much as you want, we’ll make more. This DNA2 DoubleHelix line is only 0.065 in. thick yet has over 100 lbs. of tensile strength. That thin diameter means it can be spun faster, and its solid construction tears through thicker grass. Regularly maintained lawns are healthier lawns. And sharp new string is the easiest way to ensure your edges will be clean and the grass around your home, deck, trees, shrubs, and landscaping stays trimmed. These spools are specially made for Worx string trimmers and edgers, so are unlikely to fit or perform well with string trimmers and edgers of other brands. These spools are compatible with our 20V and 32V trimmer and edger models. They even work with one of our 40V trimmers. These spools can be used in the following Worx trimmer/edger models: WG122, 150, 151, 152, 153, 154, 155, 156, 157, 160, 162, 163, 165, 166, 167, 170, 175, 180 Series. We strongly advise that Worx users follow standard safety guidelines while using Worx products, like wearing safety eyewear, gloves, appropriate shoes and clothing, and keeping hair tied back. Always read the owner’s manual for additional safety instructions before operating any tool.