The StopTech Sport Rotor is a 1-piece direct replacement brake disc for your factory braking system and stock calipers. It features a unique cross-drilled and slotted surface that aids in dissipating heat and brake dust, increasing initial bite and improving performance in wet conditions. The black e-coat finish protects against corrosion on the hub and vanes. This specific part (127.40017L) is the Left Rear position rotor. For a complete rear axle set, it is recommended to pair this with the Right Rear rotor (127.40017R). Key features: Improved cooling, better gas evacuation, and enhanced aesthetics.