PERMANENT REPAIR - Guaranteed for the Life of the Tire - BlackJack Tire Repair uses twelve strands of high-tensile fiber. Each strand of fiber is individually impregnated with our live butyl vulcanizing rubber compound. Carbon black makes rubber stronger and matches the color of the tire. BlackJack conforms to the size and shape of the injury, sealing out moisture and dirt. The soft malleable repair conforms to the shape of the injury eliminating stress to the belts.