PRO Twist by Rino-Tuff is a professional grade trimmer that outperforms other lines on the market. Up to 15% longer runtime for cordless trimmers. The aerodynamic twist shape reduces line resistance and vibration, keeping the trimmer from slowing down, using less battery energy and cutting more. Scientifically engineered to be more durable and last up to 50% longer than residential trimmer line. Impact modifiers are embedded within the nylon to keep your line from breaking away when trimming against obstacles as often as other products on the market. That means cutting more with fewer stops to get the job done faster.