24 Plies of a custom made high tensile (350 lb break strength) chemical resistant nylon yarn Each yarn is immersed in a unique proprietary rubber sealant system-250% rubber to yarn The patented manufacturing process assures the final Safety Seal repair has an equal amount of rubber sealant (250% rubber to yarn) through-out the Safety Seal Repair Makes a perfect seal in all tubeless tires (including run-flats) 4" Strings, 60 per pack