This is a new Currie Jeep JK Wrangler rear disc brake rotor for use with our full floating JK rearend units. These rotors are most commonly sold when a customer who buys our JK bolt-in rearend package, intending to use the factory brakes, would like to purchase new rotors that have already been bored to 4.250" to clear the floater hub and drilled to the 5 on 5 1/2" wheel bolt pattern. These rotors offer a set of 1/2" and and a set of 5/8" hole options. For a pair of rotors, 2 of this part number would need to be purchased.