Clutch Masters Flywheels are designed and tested to ensure the safety and quality of every flywheel. Years of R&D has given us the knowledge and firsthand experience to choose wisely the best material to manufacture flywheels that will surpass your expectations. Depending on the application, the majority of Clutch Masters flywheels are made from 6061 T6 Billet Aluminum, 1045 or 4140 Billet Steel. Clutch Masters Flywheels are SFI Certified meeting performance standards for the automotive and motorsport industry.