The Shakespeare Impact Trimmer Line is 20% more durable than our current professional grade line. The aerodynamic twisted shape reduces line resistance and vibration, keeping the trimmer from slowing down, using less battery energy and cutting more, yielding up to 15% longer runtime for cordless trimmers. 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. 24% biodegradation within 1 year via ASTM D5511 testing method in an anaerobic landfill. Anaerobic landfills may not be available in your area. Trimmer line remnants left in the yard may not necessarily experience this same level of biodegradation. The results of those tests are still pending.< li>