PRIME Composite Plain Vented Rear Driver Side Brake Rotor (09.D902.13) by Brembo®. Quantity: 1 Per Pack. The Composite brake disc is dedicated to the highest-performance applications and is perfectly interchangeable with the original disc. It has an aluminium hat connected to the special cast iron braking surface by steel pins. This solution makes the disc lighter for improved handling of the car. The sophisticated design and superior construction of these discs will give you enhanced cooling, increased resistance to fade and more consistent braking.