Clutch Masters 2-Piece Steel/Billet Aluminum Flywheels for the 2011, 2012, 2013, and 2014 Ford Mustang GT 5.0L V8 are made from the highest quality 6061-T6 or better grade aluminum. This material is chosen for its properties, which are far more suitable for the environment than the one-piece chromoly units, when it comes to heat dissipation and serviceability. The replaceable friction surface used is extremely durable high carbon steel. This permits mating with any type of clutch friction material without concern. The starter ring gears are made of high carbon heat-treated steel for long lasting durability. The unit is buttoned together with military grade fasteners to make the premier flywheel in the industry.