Fidanza Aluminum Flywheels are made from 6061 T6 billet aluminum for superior strength and weight reduction. Fidanza also offers 1045 high carbon steel flywheels which are incredibly strong and can withstand the rigors of the most extreme engines, drivers and conditions. Fidanza flywheels are CNC machined at a constant speed for precise fit and finish, and feature a replaceable 1045 high-carbon steel friction plate with AN military-grade fasteners and a hardened 1050 ring gear. You will never have to replace your flywheel again as you can just swap friction plates, and reinstall. All these features make this a quality lightweight flywheel at a great price.