3 1/8" Round Radial Patch; Thick Rubber Reinforced radial patch is one of the finest tire patches made today. BlackJack radial patches are thick, rubber-reinforced patches which allow placement on the tire in any direction. This repair can also be used on bias-ply tires. These patches work best when used with any of our string repair units. These patches are of a 2 piece construction made of virgin rubber on a bed of black cushion gum.