The unsurpassed braking capacity of the Forged Narrow Superlite 4R four - piston caliper serves as the base of this 12.19 big rotor kit for the popular Jeep CJ vehicles, Kit fitment starts with 1981 models originally equipped with 5 bolt drive flange rotors and fitment continues to all 82 - 86 year vehicles. SL4R kits are engineered application specific to these vehicles, providing simplified installation and full compatibility with OE master cylinder output and ABS functions where used. Big brake kits offer increased brake capacity and complimentary style with wheel, tire, and suspension upgrades. Optional caliper finishes and rotor designs simplify personalizing the style and braking requirements of any application.