WORX 6 pack timmer/edger line is made from a patented copolymer nylon resin and synthetic material designed with an oval aerodynamic shape known as DoubleHelix DNALINE2. This patented design increases edging life up to 25-percent compared to normal use conditions. This patented 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. DNA2 trimmer line is durable and flexible for longer life.