BlackJacks Tire Repairs are manufactured using TWELVE strands of high-tensile fibers. Many competitors use cotton or polyester fiber and with as few as seven strands. Each BlackJack strand of fiber is individually impregnated with live butyl rubber. This compound is developed using carbon black, giving the repair its black color, making the repair almost invisible in the tire. BlackJack Repairs conform to the size and shape of the injury, sealing out moisture and dirt, eliminating stress to the belts and preserving the tire integrity. This is the reason that BlackJack Tire Repairs are a PERMANENT repair. Small diameter repairs are approximately 3/16 inches (4.8 mm) in diameter and the Large diameter repairs are approximately 1/4 inches (6.4 mm) in diameter.