Never pay for the cost of spools over the lifetime of your qualifying Worx trimmer. That~s how excited we are about the DNA2 DoubleHelix cutting line. We want you to have as many as you need, and to tell others about its aerodynamic design, which makes for cleaner cuts. Sharper cuts encourage growth, so you~re going to have the healthiest lawn on the block. Each spool comes pre-wound, so you can just pop it into your trimmer and get to work. Each spool contains 10 feet of string, and so each 6 pack we send has 60 feet of line. Trim and edge as much as you want, we~ll make more. This DoubleHelix line is only 0.065~ 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. These spools are compatible with over 25 of our 20V and 32V trimmer and edger models. It even works with one of our 40V trimmers. So go ahead, order more spools, you~ve earned them.