Product Description CORDLESS TRIMMER LINE 2.4mm Undulated Nylon Line. SP66 Undulated is the only patented line that has been specifically developed and designed for battery powered machines. Its unique design and composition reduce drag resulting in a longer battery run time and less battery changes on the job. SP66 has a patented raw material blend which is very hard wearing and has a higher melting point that eliminates welding in the head. The unique shaping process provides an aerodynamic profile with less air resistance, less vibrations and reduced decibel emissions. Features premium quality long Life Longer Battery run time Made in France