This system features brackets to relocated your factory caliper to allow the use of our 15 inch 1pc slot, drill, zinc plated directional rotors. The EradiSpeed1 is a simple bolt on (no bleeding of the brakes required). By increasing rotors diameter, you increase torque and leverage of the brake. A very popular upgrade for customers increasing wheel diameter that want to improve braking, as well as a visual impact behind the open wheel Further, the directionally vaned structure of the rotor improves cooling efforts.Rotor Diameter:15 inch 1-piecePiston Count:Uses your existing stock calipersPad Type:Uses stock pads. Minimum Wheel Size:19 inchIncludes:15 inch 1pc slot, drill, zinc rotors, brackets and hardwareNotes:Designed to be used with 2004-2008 Ford F-150s 4wd