This extremely natural-gut-like performance multi-fiber string has been improved with a new patented coating process that helps eliminate the notching due to friction and court debris. Exceptional tension maintenance, thanks to the patented "high pressure-resin-misting", allows more string fibers and less resin. This also helps create exceptional shock and vibration reduction. Power Fiber II - developed for all racquets and playing style for today's players who demand top performance!