StopTech 2-Piece Slotted AeroRotor Kits are designed to replace Original Equipment rotors, while retaining the factory brake calipers. The same size as Original Equipment, the two-piece, directional, floating AeroRotor offers improved cooling, braking and handling. AeroRotor rings feature StopTech's patented AeroVane® internal vane design to optimize airflow. The rings are pre-assembled to billet aluminum AeroHats for additional cooling functionality. Elongated drive pin slots allow separate expansion of the rotor and hat to resist coning.